TOPSHOT - Indian women take pictures on a boat as migratory birds fly overhead on the Yamuna River on a morning of heavy air pollution in New Delhi on November 20, 2018. - Smog levels spike during winter in Delhi, when air quality often eclipses the World Health Organization's safe levels. Cooler air traps pollutants -- such as from vehicles, building sites and farmers burning crops in regions outside the Indian capital -- close to the ground. (Photo by Noemi Cassanelli / AFP)