Buildings and monuments are largely obscured by the haze The smoke from fields mixes with vehicle emissions and construction dust, making it the world’s most polluted capital NEW DELHI: Schools in India’s capital are shut after air quality plunged to a severe category for the third consecutive day, enveloping New Delhi in a thick gray haze of noxious air. According to the state-run Central Pollution Control Board, the air quality index Thursday exceeded 460, nine times the level recommended by the WHO. Buildings and monuments are largely obscured by the haze and an official health advisory has asked residents to avoid all physical activity outdoors. Air pollution in northern India, including New Delhi, peaks in the winter due to smoke from agricultural fires. The smoke from fields mixes with vehicle emissions and construction dust, making it the world’s most polluted capital.