Farm fires in north India are at their lowest in eight years, but Delhi’s still choking

Crop residue burning in northern Indian farmlands during this time of the year is at its lowest level in eight years, according to images from NASA satellites that map land fires. After harvesting the September crop—often manually with a sickle—farmers in the capital city’s neighbouring states of Haryana and Punjab traditionally burn the residue stalks to clear the field for the next sowing season in November. Winds from Punjab to Haryana and even parts of Pakistan bring PM 2.5 to the northern Indian plains, particularly Delhi, around the beginning of winter.