Over the last few years, the national capital and adjoining regions in Northern India have witnessed worsening of air pollution during the winter season. In November 2019, a ‘public health emergency’ was declared in Delhi after air quality plunged to ‘severe plus’ levels as the Air Quality Index (AQI) crossed 500 in many locations.

The various causes of this air pollution crisis in Northern India in winters are

• Lack of winds in the winter season: Dust particles and pollutants in the air are unable to move and get locked in the stagnant air and affect weather conditions, resulting in smog.
• Geographical location: Winds arriving from the coasts pick pollutants along the way and get ‘trapped’ right before the Himalayas.
• Stubble burning: Crop residue burning during winter (in the states of Punjab, Haryana and UP) is one of the chief causes for rising air pollution levels in Northern India.
• Dust storms: Destruction of the Aravallis that protects north India from dust storms has increased impact. Also, a study in 2017, “multi-day dust storm” in Iraq, Kuwait and Saudi Arabia was one of the main causes of Delhi’s smog.

These factors exacerbate the impact of the following prevailing sources of pollution

• Large scale construction: It is responsible for increasing dust and pollution in the air.
• Industrial pollution: As per the study by TERI, industries contribute 30 per cent to PM2.5 levels, with 14 per cent from small industries. India is the world’s second largest coal burner after China.
• Vehicular Pollution: TERI’s study shows that vehicle pollution is the cause of 28 percent of PM2.5 emissions. For instance: The total number of vehicles in Delhi increased from 4.24 million in 2004 to more than 10.8 million in March 2018.

According to the World Bank, health-care fees and productivity losses from pollution cost India as much as 8.5 per cent of GDP. In 2017, the Lancet Commission on Pollution and Health attributed an estimated 1.1 million premature deaths to air pollution in India.

Considering this impact, government has initiated various measures such as

• Environmental Pollution (Prevention and Control) Authority enforce Graded Response Action Plan (GRAP): Comprises graded measures for each source framed according to the Air Quality Index categories. For instance, during ‘very poor air quality, it recommends banning diesel generators and parking fee increased by three to four times.
• National Clean Air Programme (NCAP): Is a pollution control initiative to cut the concentration of particles (PM10 & PM2.5) by 20-30% by 2024.
• Central Sector Scheme on ‘Promotion of Agricultural Mechanization for In-Situ Management of Crop Residue in the States of Punjab, Haryana, Uttar Pradesh and NCT of Delhi’ for the period from 2018-19 to 2019-20 has been launched to address air pollution and to subsidize machinery required for in-situ management of crop residue.
• Advancing Bharat Stage-VI norms: To April 2018 from April 2020. Delhi became the first city running on BS VI fuels.
• The Environment Ministry has notified environmental norms to reduce emission of PM 10, SO2 and oxide of nitrogen by thermal power plants.

Further, efforts like Intended Nationally Determined Contribution and National electric mobility mission plan 2020 by India would also improve the emissions intensity.