Rydberg constant

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Rydberg_constant 

In spectroscopy, the Rydberg constant, symbol ${\displaystyle R_{\mathrm{\infty }}}$ for heavy atoms or ${\displaystyle R_{\text{H}}}$ for hydrogen, named after the Swedish physicist Johannes Rydberg, is a physical constant relating to the electromagnetic spectra of an atom. The constant first arose as an empirical fitting parameter in the Rydberg formula for the hydrogen spectral series, but Niels Bohr later showed that its value could be calculated from more fundamental constants via his Bohr model. As of 2018, ${\displaystyle R_{\mathrm{\infty }}}$ and electron spin g-factor are the most accurately measured physical constants.

The constant is expressed for either hydrogen as ${\displaystyle R_{\text{H}}}$, or at the limit of infinite nuclear mass as ${\displaystyle R_{\mathrm{\infty }}}$. In either case, the constant is used to express the limiting value of the highest wavenumber (inverse wavelength) of any photon that can be emitted from an atom, or, alternatively, the wavenumber of the lowest-energy photon capable of ionizing an atom from its ground state. The hydrogen spectral series can be expressed simply in terms of the Rydberg constant for hydrogen ${\displaystyle R_{\text{H}}}$ and the Rydberg formula.

In atomic physics, Rydberg unit of energy, symbol Ry, corresponds to the energy of the photon whose wavenumber is the Rydberg constant, i.e. the ionization energy of the hydrogen atom in a simplified Bohr model.

Value

Rydberg constant

The CODATA value is

${\displaystyle R_{\mathrm{\infty }}=\frac{m_{\text{e}}{e}^4}{8{\epsilon }_0^2{h}^{3}c}}$ = 10973731.568160(21) m⁻¹,

where

• ${\displaystyle m_{\text{e}}}$ is the rest mass of the electron,
• ${\displaystyle e}$ is the elementary charge,
• ${\displaystyle {\epsilon }_0}$ is the permittivity of free space,
• ${\displaystyle h}$ is the Planck constant, and
• ${\displaystyle c}$ is the speed of light in vacuum.

The Rydberg constant for hydrogen may be calculated from the reduced mass of the electron:

${\displaystyle R_{\text{H}}=R_{\mathrm{\infty }}\frac{m_{\text{p}}}{m_{\text{e}}+m_{\text{p}}}\approx 1.09678\times {10}^7{\text{ m}}^{-1},}$

where

• ${\displaystyle m_{\text{e}}}$ is the mass of the electron,
• ${\displaystyle m_{\text{p}}}$ is the mass of the nucleus (a proton).

Rydberg unit of energy

The Rydberg unit of energy is equivalent to joules and electronvolts in the following manner:

${\displaystyle 1\text{Ry}\equiv hc{R}_{\mathrm{\infty }}=\frac{m_{\text{e}}{e}^4}{8{\epsilon }_0^2{h}^2}=\frac{e^2}{8\pi {\epsilon }_0{a}_0}=2.1798723611035(42)\times {10}^{-18}\text{J}=13.605693122994(26)\text{eV}.}$

Rydberg frequency

${\displaystyle c{R}_{\mathrm{\infty }}=3.2898419602508(64)\times {10}^{15}\text{Hz}.}$

Rydberg wavelength

${\displaystyle \frac{1}{R_{\mathrm{\infty }}}=9.112670505824(17)\times {10}^{-8}\text{m}}$.

The angular wavelength is

${\displaystyle \frac{1}{2\pi R_{\mathrm{\infty }}}=1.4503265557696(28)\times {10}^{-8}\text{m}}$.

Occurrence in Bohr model

Main article: Bohr model

The Bohr model explains the atomic spectrum of hydrogen (see hydrogen spectral series) as well as various other atoms and ions. It is not perfectly accurate, but is a remarkably good approximation in many cases, and historically played an important role in the development of quantum mechanics. The Bohr model posits that electrons revolve around the atomic nucleus in a manner analogous to planets revolving around the sun.

In the simplest version of the Bohr model, the mass of the atomic nucleus is considered to be infinite compared to the mass of the electron, so that the center of mass of the system, the barycenter, lies at the center of the nucleus. This infinite mass approximation is what is alluded to with the ${\displaystyle \mathrm{\infty }}$ subscript. The Bohr model then predicts that the wavelengths of hydrogen atomic transitions are (see Rydberg formula):

${\displaystyle \frac{1}{\lambda }=\mathrm{R}\mathrm{y}\cdot \frac{1}{hc}\left(\frac{1}{n_1^2}-\frac{1}{n_2^2}\right)=\frac{m_{\text{e}}{e}^4}{8{\epsilon }_0^2{h}^{3}c}\left(\frac{1}{n_1^2}-\frac{1}{n_2^2}\right)}$

where n₁ and n₂ are any two different positive integers (1, 2, 3, ...), and ${\displaystyle \lambda }$ is the wavelength (in vacuum) of the emitted or absorbed light.

${\displaystyle \frac{1}{\lambda }=R_M\left(\frac{1}{n_1^2}-\frac{1}{n_2^2}\right)}$

where ${\displaystyle R_M=\frac{R_{\mathrm{\infty }}}{1+\frac{m_{\text{e}}}{M}},}$ and M is the total mass of the nucleus. This formula comes from substituting the reduced mass of the electron.

Precision measurement

See also: Precision tests of QED

The Rydberg constant is one of the most precisely determined physical constants, with a relative standard uncertainty of under 2 parts in 10¹². This precision constrains the values of the other physical constants that define it.

Since the Bohr model is not perfectly accurate, due to fine structure, hyperfine splitting, and other such effects, the Rydberg constant ${\displaystyle R_{\mathrm{\infty }}}$ cannot be directly measured at very high accuracy from the atomic transition frequencies of hydrogen alone. Instead, the Rydberg constant is inferred from measurements of atomic transition frequencies in three different atoms (hydrogen, deuterium, and antiprotonic helium). Detailed theoretical calculations in the framework of quantum electrodynamics are used to account for the effects of finite nuclear mass, fine structure, hyperfine splitting, and so on. Finally, the value of ${\displaystyle R_{\mathrm{\infty }}}$ is determined from the best fit of the measurements to the theory.

Alternative expressions

The Rydberg constant can also be expressed as in the following equations.

${\displaystyle R_{\mathrm{\infty }}=\frac{{\alpha }^2{m}_{\text{e}}c}{4\pi \hslash }=\frac{{\alpha }^2}{2{\lambda }_{\text{e}}}=\frac{\alpha }{4\pi a_0}}$

and in energy units

${\displaystyle \text{Ry}=hc{R}_{\mathrm{\infty }}=\frac{1}{2}{m}_{\text{e}}{c}^2{\alpha }^2=\frac{1}{2}\frac{e^4{m}_{\text{e}}}{(4\pi {\epsilon }_0{)}^2{\hslash }^2}=\frac{1}{2}\frac{m_{\text{e}}{c}^2{r}_{\text{e}}}{a_0}=\frac{1}{2}\frac{hc{\alpha }^2}{{\lambda }_{\text{e}}}=\frac{1}{2}h{f}_{\text{C}}{\alpha }^2=\frac{1}{2}\hslash {\omega }_{\text{C}}{\alpha }^2=\frac{1}{2m_{\text{e}}}{\left({\displaystyle \frac{\hslash }{a_0}}\right)}^2=\frac{1}{2}\frac{e^2}{(4\pi {\epsilon }_0)a_0}.}$

where

• ${\displaystyle m_{\text{e}}}$ is the electron rest mass,
• ${\displaystyle e}$ is the electric charge of the electron,
• ${\displaystyle h}$ is the Planck constant,
• ${\displaystyle \hslash =h/2\pi }$ is the reduced Planck constant,
• ${\displaystyle c}$ is the speed of light in a vacuum,
• ${\displaystyle {\epsilon }_0}$ is the electrical field constant (permittivity) of free space,
• ${\displaystyle \alpha =\frac{1}{4\pi {\epsilon }_0}\frac{e^2}{\hslash c}}$ is the fine-structure constant,
• ${\displaystyle {\lambda }_{\text{e}}=h/m_{\text{e}}c}$ is the Compton wavelength of the electron,
• ${\displaystyle f_{\text{C}}=m_{\text{e}}{c}^2/h}$ is the Compton frequency of the electron,
• ${\displaystyle {\omega }_{\text{C}}=2\pi f_{\text{C}}}$ is the Compton angular frequency of the electron,
• ${\displaystyle a_0=\frac{4\pi {\epsilon }_0{\hslash }^2}{e^2{m}_{\text{e}}}}$ is the Bohr radius,
• ${\displaystyle r_{\mathrm{e}}=\frac{1}{4\pi {\epsilon }_0}\frac{e^2}{m_{\mathrm{e}}{c}^2}}$ is the classical electron radius.

The last expression in the first equation shows that the wavelength of light needed to ionize a hydrogen atom is 4π/α times the Bohr radius of the atom.

The second equation is relevant because its value is the coefficient for the energy of the atomic orbitals of a hydrogen atom: ${\displaystyle E_n=-hc{R}_{\mathrm{\infty }}/n^2}$.

Environmental issues in India

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Environmental_issues_in_India 

 

A satellite picture, taken in 2004, shows thick haze and smog along the Ganges Basin in northern India. Major sources of aerosols in this area are believed to be smoke from biomass burning in the northwest part of India, and air pollution from large cities in northern India since the 1980s. Dust from deserts in Pakistan and the Middle East may also contribute to the mix of aerosols.

 

Solid waste adds to water pollution in India, 2005

There are many environmental issues in India. Air pollution, water pollution, garbage, domestically prohibited goods and pollution of the natural environment are all challenges for India. Nature is also causing some drastic effects on India. The situation was worse between 1947 through 1995. According to data collected and environmental assessments studied by World Bank experts, between 1995 through 2010, India has made some of the fastest progress in addressing its environmental issues and improving its environmental quality in the world. Still, India has a long way to go to reach environmental quality similar to those enjoyed in developed economies. Pollution remains a major challenge and opportunity for India.

Environmental issues are one of the primary causes of disease, health issues and long term livelihood impact for India.

Law and policies

Main articles: Environmental policy of India and Indian environmental law

British rule of India saw several laws related to the environment. Amongst the earliest ones were Shore Nuisance (Bombay and Kolkata) Act of 1853 and the Oriental Gas Company Act of 1857. The Indian Penal Code of 1860, imposed a fine on anyone who voluntarily fouls the water of any public spring or reservoir. In addition, the Code penalised negligent acts. British India also enacted laws aimed at controlling air pollution. Prominent amongst these were the Bengal Smoke Nuisance Act of 1905 and the Bombay Smoke Nuisance Act of 1912. Whilst these laws failed in having the intended effect, British-enacted legislations pioneered the growth of environmental regulations in India.

Upon independence from Britain, India adopted a constitution and numerous British-enacted laws, without any specific constitutional provision on protecting the environment. India amended its constitution in 1976. Article 48(A) of Part IV of the amended constitution, read: The State shall endeavour to protect and improve the environment and to safeguard the forests and wildlife of the country. Article 51 A (g) imposed additional environmental mandates on the Indian state.

Other Indian laws from recent history include the Water (Prevention and Control of Pollution) Act of 1974, the Forest (Conservation) Act of 1980, and the Air (Prevention and Control of Pollution) Act of 1981. The Air Act was inspired by the decisions made at Stockholm Conference. The Bhopal gas tragedy triggered the Government of India to enact the Environment (Protection) Act of 1986. India has also enacted a set of Noise Pollution (Regulation & Control) Rules in 2000.

In 1985, the Indian government created the Ministry of Environment and Forests. This ministry is the central administrative organisation in India for regulating and ensuring environmental protection.

Despite the active passage of laws by the central government of India, the reality of environmental quality mostly worsened between 1947 and 1990. Rural poor had no choice, but to sustain life in whatever way possible. Air emissions increased, water pollution worsened, forest cover decreased.

Starting in the 1990s, reforms were introduced. Since then, for the first time in Indian history, major air pollutant concentrations have dropped in every 5-year period. Between 1992 and 2010, satellite data confirms India's forest coverage has increased for the first time by over 4 million hectares, a 7% increase. In August 2019, the Indian government imposed a nationwide ban on single-use plastics that will take effect on 2 Oct.

Possible causes

Some have cited economic development as the cause regarding the environmental issues. It is suggested that India's growing population is the primary cause of India's environmental degradation. Empirical evidence from countries such as Japan, England and Singapore, each with population density similar to or higher than that of India, yet each enjoying environmental quality vastly superior to India's, suggests population density may not be the only factor affecting India's issues.

Major issues

Floods are a significant environmental issue for India. It causes soil erosion, destruction of wetlands and wide migration of solid wastes.

 

Development of carbon dioxide emissions

Major environmental issues are forests and agricultural degradation of land, resource depletion (such as water, mineral, forest, sand, and rocks), environmental degradation, public health, loss of biodiversity, loss of resilience in ecosystems, livelihood security for the poor.

The major sources of pollution in India include the rapid burning of fuelwood and biomass such as dried waste from livestock as the primary source of energy, lack of organised garbage and waste removal services, lack of sewage treatment operations, lack of flood control and monsoon water drainage system, diversion of consumer waste into rivers, using large land area for burial purposes, cremation practices near major rivers, government mandated protection of highly polluting old public transport, and continued operation by Indian government of government-owned, high emission plants built between 1950 and 1980.

Air pollution, poor management of waste, growing water scarcity, falling groundwater tables, water pollution, preservation and quality of forests, biodiversity loss, and land/soil degradation are some of the major environmental issues India faces today.

India's population growth adds pressure to environmental issues and its resources. Rapid urbanization has caused a buildup of heavy metals in the soil of the city of Ghaziabad, and these metals are being ingested through contaminated vegetables. Heavy metals are hazardous to people's health and are known carcinogens.

Population growth and environmental quality

Public dumping of garbage alongside a road in Kolkata.

There is a long history of study and debate about the interactions between population growth and the environment. According to a British thinker Malthus, for example, a growing population exerts pressure on agricultural land, causing environmental degradation, and forcing the cultivation of land of higher as well as poorer quality. This environmental degradation ultimately reduces agricultural yields and food availability, famines and diseases and death, thereby reducing the rate of population growth.

Population growth, because it can place increased pressure on the assimilative capacity of the environment, is also seen as a major cause of air, water, and solid-waste pollution. The result, Malthus theorised, is an equilibrium population that enjoys low levels of both income and Environmental quality. Malthus suggested positive and preventative forced control of human population, along with abolition of poor laws.

Malthus theory, published between 1798 and 1826, has been analysed and criticised ever since. The American thinker Henry George, for example, observed with his characteristic piquancy in dismissing Malthus: "Both the jayhawk and the man eat chickens; but the more jayhawks, the fewer chickens, while the more men, the more chickens." Similarly, the American economist Julian Lincoln Simon criticised Malthus's theory. He noted that the facts of human history have proven the predictions of Malthus and of the Neo-Malthusians to be flawed. Massive geometric population growth in the 20th century did not result in a Malthusian catastrophe. The possible reasons include: increase in human knowledge, rapid increases in productivity, innovation and application of knowledge, general improvements in farming methods (industrial agriculture), mechanisation of work (tractors), the introduction of high-yield varieties of rice and wheat among other plants (Green Revolution), the use of pesticides to control crop pests.

More recent scholarly articles concede that whilst there is no question that population growth may contribute to environmental degradation, its effects can be modified by economic growth and modern technology. Research in environmental economics has uncovered a relationship between environmental quality, measured by ambient concentrations of air pollutants and per capita income. This so-called environmental Kuznets curve shows environmental quality worsening up until about $5,000 of per capita income on purchasing parity basis, and improving thereafter. The key requirement, for this to be true, is continued adoption of technology and scientific management of resources, continued increases in productivity in every economic sector, entrepreneurial innovation and economic expansion.

Other data suggest that population density has little correlation to environmental quality and human quality of life. India's population density, in 2011, was about 368 human beings per square kilometre. Many countries with population density similar or higher than India enjoy environmental quality as well as human quality of life far superior than India. For example: Singapore (7148 /km²), Hong Kong (6349 /km²), South Korea (487 /km²), Netherlands (403 /km²), Belgium (355 / km²), England (395 /km²) and Japan (337/ km²).

Water pollution

Main article: Water pollution in India

 

The Taj Mahal next to the Yamuna river

India has major water pollution issues. Discharge of untreated sewage is an important cause for pollution of surface and ground water in India, since there is a large gap between the generation and treatment of domestic waste water. The problem is not only that India lacks sufficient treatment capacity but also that the sewage treatment plants that exist do not operate and are not maintained. The majority of government-owned sewage treatment plants remain closed most of the time due to improper design, poor maintenance, or lack of reliable electricity supply, along with severe understaffing. The waste water generated in these areas normally percolates in the soil or evaporates. The uncollected waste accumulates in urban areas, causing unhygienic conditions and releasing pollutants that reach to surface and groundwater.

According to a World Health Organization study, out of India's 3,119 towns and cities, just 209 had partial sewage treatment facilities, and only 8 have full wastewater treatment facilities (1992). Over 100 Indian cities dump untreated sewage directly into the Ganges River. Investment is needed to bridge the gap between 29,000 million litre per day of sewage India generates, and a treatment capacity of mere 6000 million litre per day.

Other sources of water pollution include agriculture runoff and small scale factories along the rivers and lakes of India. Fertilizers and pesticides used in agriculture in northwestern India have been found in rivers, lakes and ground water. Flooding during monsoons worsens India's water pollution problem, as it washes and moves all sorts of solid garbage and contaminated soils into its rivers and wetlands.

Sewage and polluted solid waste mix up with Bidyadhari River, Guma, India 2022

Water resources

According to NASA groundwater declines are highest on Earth between 2002 and 2008 in northern India. Agricultural productivity is dependent on irrigation. A collapse of agricultural output and severe shortages of potable water may influence 114 million residents in India. In July 2012, about 670 million people or 10% of the world’s population lost power blame on the severe drought restricting the power delivered by hydroelectric dams.

Air pollution

Main article: Air pollution in India

 

A rural stove using biomass cakes, fuelwood and trash as cooking fuel. Surveys suggest over 100 million households in India use such stoves (chullahs) every day, 2–3 times a day. It is a major source of air pollution in India, and produces smoke and numerous indoor air pollutants at concentrations 5 times higher than coal. Clean burning fuels and electricity are unavailable in rural parts and small towns of India because of poor rural highways and limited energy generation infrastructure.

Air pollution in India is a serious issue, with the major sources being biomass burning, fuel adulteration, vehicle emission, and traffic congestion. Air pollution is also the main cause of the Asian brown cloud, which has been causing the monsoon season to be delayed. India is the world's largest consumer of fuelwood, agricultural waste, and biomass for energy purposes. Traditional fuel (fuelwood, crop residue and dung cake) dominates domestic energy use in rural India and account for about 90% of the total. In urban areas, traditional fuel constitutes about 24% of the total. Fuel wood, agricultural waste and biomass cake burning release over 165 million tonnes of combustion products every year. These biomass-based household stoves in India are also a leading source of greenhouse emissions, which contribute to climate change.

The annual crop burning practice in northwest India, north India and eastern Pakistan, before and after monsoons, from April and May to October to November, are a major seasonal source of air pollution since the 1980s. Approximately 500 million tons of crop residue are burnt in the open, releasing NOx, SOx, PAHs and particulate matter into the air. This burning has been found to be a leading cause of smog and haze problems through the winter over Punjab, cities such as Delhi, and major population centers along the rivers through West Bengal. In other states of India, rice straw and other crop residue burning in open is a major source of air pollution.

Vehicle emissions are another source of air pollution. Vehicle emissions are worsened by fuel adulteration and poor fuel combustion efficiencies from traffic congestion and low density of quality, high speed road network per 1000 people. In order to reduce air pollution effects India is introducing hybrid and electric vehicles as per the Faster Adoption and Manufacturing of Electric vehicles in India scheme. While challenges are slowing down the development cleaner combustion fuels are being use in motor vehicles. As of now Delhi Transport Corporation is the world's largest operator of CNG bus fleet. Many Indian cities are testing out with cleaner fossil fuels mostly CNG fuel and renewable biofuels such as biodiesel and E85 blended petroleum. In June 2020, the supreme court promised that in order to improve emissions from vehicles all BS4 vehicles will be upgraded to BS6 standards.

On per capita basis, India is a small emitter of carbon dioxide greenhouse. In 2009, IEA estimates that it emitted about 1.4 tons of gas per person, in comparison to the United States’ 17 tons per person, and a world average of 5.3 tons per person. However, India was the third largest emitter of total carbon dioxide in 2009 at 1.65 Gt per year, after China (6.9 Gt per year) and the United States (5.2 Gt per year). With 17 percent of world population, India contributed some 5 percent of human-sourced carbon dioxide emission; compared to China's 24 percent share.

The Air (Prevention and Control of Pollution) Act was passed in 1981 to regulate air pollution and there have been some measurable improvements. However, the 2012 Environmental Performance Index ranked India at 177th position out of 180 countries in 2018,as having the poorest relative air quality out of 132countries. Of the world's 30 most polluted cities, India is home to 21 as of 2020.

Solid waste pollution

See also: Solid waste policy in India

 

Trash and garbage disposal services, responsibility of local government workers in India, are ineffective. Solid waste is routinely seen along India's streets and shopping plazas. Image shows solid waste pollution along a Jaipur street, a 2011 image.

Trash and garbage are a common sight in urban and rural areas of India. It is a major source of pollution. Indian cities alone generate more than 100 million tons of solid waste a year. Street corners are piled with trash. Public places and sidewalks are despoiled with filth and litter, rivers and canals act as garbage dumps. In part, India's garbage crisis is from rising congestion. India's waste problem also points to a stunning failure of governance. The tourism regions in the country mainly hill stations are also facing this issue in the recent years.

In 2000, India's Supreme Court directed all Indian cities to implement a comprehensive waste-management programme that would include household collection of segregated waste, recycling and composting. These directions have simply been ignored. No major city runs a comprehensive programme of the kind envisioned by the Supreme Court.

Indeed, forget waste segregation and recycling directive of the India's Supreme Court, the Organisation for Economic Cooperation and Development estimates that up to 40 percent of municipal waste in India remains simply uncollected. Even medical waste, theoretically controlled by stringent rules that require hospitals to operate incinerators, is routinely dumped with regular municipal garbage. A recent study found that about half of India's medical waste is improperly disposed of.

Municipalities in Indian cities and towns have waste collection employees. However, these are unionised government workers and their work performance is neither measured nor monitored.

Some of the few solid waste landfills India has, near its major cities, are overflowing and poorly managed. They have become significant sources of greenhouse emissions and breeding sites for disease vectors such as flies, mosquitoes, cockroaches, rats, and other pests.

Waste collection truck in Ahmedabad, Gujarat

In 2011, several Indian cities embarked on waste-to-energy projects of the type in use in Germany, Switzerland and Japan. For example, New Delhi is implementing two incinerator projects aimed at turning the city’s trash problem into electricity resource. These plants are being welcomed for addressing the city’s chronic problems of excess untreated waste and a shortage of electric power. They are also being welcomed by those who seek to prevent water pollution, hygiene problems, and eliminate rotting trash that produces potent greenhouse gas methane. The projects are being opposed by waste collection workers & local unions who fear changing technology may deprive them of their livelihood and way of life.

Noise pollution

Noise pollution or noise disturbance is the most efficiently changing and disturbing or excessive noise that may harm the activity or balance of human or animal life. The source of most outdoor noise worldwide is mainly caused by machines and transportation systems, motor vehicles, aircraft, and trains. In India the outdoor noise is also caused by loud music during festival seasons.Outdoor noise is summarized by the word environmental noise. Poor urban planning may give rise to noise pollution, since side-by-side industrial and residential buildings can result in noise pollution in the residential areas.

Indoor noise can be caused by machines, building activities, and music performances, especially in some workplaces. Noise-induced hearing loss can be caused by outside (e.g. trains) or inside (e.g. music) noise.

High noise levels can contribute to cardiovascular effects in humans and an increased incidence of coronary artery disease. In animals, noise can increase the risk of death by altering predator or prey detection and avoidance, interfere with reproduction and navigation, and contribute to permanent hearing loss.

The Supreme Court of India which is in New Delhi gave a significant verdict on noise pollution in 2005. Unnecessary honking of vehicles makes for a high decibel level of noise in cities. The use of loudspeakers for political purposes and for sermons by temples and mosques makes noise pollution in residential areas worse.

In January 2010, Government of India published norms of permissible noise levels in urban and rural areas.

Greater adjutant perched on a pile of trash and solid waste in Assam.

Erosion of sands

In March 2009, the issue of Punjab attracted press coverage. It was alleged to be caused by flying ash ponds of thermal power stations, which reportedly lead to severe birth defects in children in the Faridkot and Bhatinda districts of Punjab. The news reports claimed the uranium levels were more than 60 times the maximum safe limit. In 2012, the Government of India confirmed that the ground water in Malwa belt of Punjab has uranium metal that is 50% above the trace limits set by the United Nations' World Health Organization. Scientific studies, based on over 1000 samples from various sampling points, could not trace the source to fly ash and any sources from thermal power plants or industry as originally alleged. The study also revealed that the uranium concentration in ground water of Malwa district is not 60 times the WHO limits, but only 50% above the WHO limit in 3 locations. This highest concentration found in samples was less than those found naturally in ground waters currently used for human purposes elsewhere, such as Finland. Research is underway to identify natural or other sources for the uranium.

Greenhouse gas emissions

Main article: Climate change in India

India was the third largest emitter of carbon dioxide, a major greenhouse gas, in 2009 at 1.65 Gt per year, after China and the United States . With 17 percent of world population, India contributed some 5 percent of human-sourced carbon dioxide emission; compared to China's 24 percent share. On per capita basis, India emitted about 1.4 tons of carbon dioxide per person, in comparison to the United States’ 17 tons per person, and a world average of 5.3 tons per person.

Forests

India had a 2018 Forest Landscape Integrity Index mean score of 7.09/10, ranking it 58th globally out of 172 countries.