Smog envelops the skyline at noon a day after Diwali festival in New Delhi, India, Friday, Oct. 20, 2017. A court ban on firework sales before the Diwali festival didn’t stop New Delhi residents from firing rockets and lighting crackers throughout Thursday night. They awoke Friday morning to acrid, smoke-filled skies and levels of dangerous, lung-clogging particulate matter known as PM2.5 that went beyond 900 parts per million — 90 times the recommended limit by the World Health Organization, and 22 times higher than India’s own limits. (AP Photo/Altaf Qadri)