File:Continued Fires and Smoke in India (MODIS 2020-12-06).jpg

English: Hazy skies continued to cover much of India in early December 2020. For several months, farmers in the richest agricultural areas – primarily Punjab and Haryana, where rice and wheat are widely grown – have used fire to clean stubble from their fields and to prepare for new plantings. This traditional agricultural method is effective on the ground, but the widespread use of fire creates heavy smoke in the region. The winds often spread a river of smoke across the Indo-Gangetic Plain and add to pollution across much of India.

On December 4, 2020, the Moderate Resolution Imaging Spectroradiometer (MODIS) on board NASA’s Terra satellite acquired a true-color image of smoke and haze stretching across the feet of the Himalaya Mountains and wrapping around the eastern coast of India. In many areas, especially in the northeast, the haze and smoke are so thick that it obscures the land from view.

India’s air pollution problems are complex and multi-factorial. Industrial pollution, dust, and automobile exhaust all are important sources of pollution. In the fall, agricultural fires are the primary source of haze. Burning typically peaks during the first week of November, a time when many farmers set fire to leftover rice stalks and straw after harvest, a practice known as stubble or paddy burning. The burning often coincides with falling temperatures and slow wind speeds, meteorological conditions that can lead to temperature inversions, which trap smoke in place.