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 per cent 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 (135 crores) 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.