Air pollution in Delhi, On 25 November 2019, the Supreme Court of India made statement. India’s Ministry of Earth Sciences published a research paper in October 2018 attributing almost 41% to vehicular emissions, 21.5% to dust and 18% to industries. The director of Centre for Science and Environment (CSE) alleged that the Society of Indian Automobile Manufacturers (SIAM) is lobbying “against the report” because it is “inconvenient” to the automobile industry.
Delhi’s pollution problem is also caused by the factor of animal agriculture, as smog and other harmful particles are produced by farmers burning their crop in other states. About 80% of agriculturally used land is used for animal agriculture, so animal agriculture can also be attributed as a factor in Delhi’s air pollution problem. Initiatives such as a 1,600 km long and 5 km wide The Great Green Wall of Aravalli green ecological corridor along Aravalli range from Gujarat to Delhi which will also connect to Shivalik hill range is being considered with planting of 1.35 billion new native trees over 10 years to combat the pollution. In December 2019, IIT Bombay, in partnership with the McKelvey School of Engineering of Washington University in St. Louis, launched the Aerosol and Air Quality Research Facility to study air pollution in India.
Air quality index of Delhi is generally Moderate (101–200) level between January to September, and then it drastically deteriorates to Very Poor (301–400), Severe (401–500) or Hazardous (500+) levels during October to December due to various factors including stubble burning, road dust, vehicle pollution and cold weather. In November 2017, in an event known as the Great Smog of Delhi, the air pollution spiked far beyond acceptable levels. Levels of PM2.5 and PM 10 particulate matter hit 999 micrograms per cubic meter, while the safe limits for those pollutants are 60 and 100 respectively.