(which is undigested grass),straw,firewood..collectively known as biomass is a major cause of pollution in bharat.....

If We Ate Less Rice, Delhi’s Air Could Be Cleaner     Charu Bahri, November 19, 2017

"..Stubble burning by farmers in Punjab and Haryana is responsible for the critical drop in the air quality in major north Indian cities, specially the Northern Capital Region.....Air pollution levels in seven other north Indian cities, analysed using IndiaSpend #Breathe air-quality sensors, were between 2-3 and 10 times above safe limits, based on the 24-hour average of PM 2.5. It led to widespread respiratory distress in Delhi and neighbouring areas..."

http://www.indiaspend.com/cover-story/if-we-ate-less-rice-delhis-air-could-be-cleaner-27363