United Airlines resumed the Newark-New Delhi flight after temporarily suspending the service because of poor air quality in India’s capital. Flight UA82 was operating Sunday, the airline said in an emailed statement. “We are monitoring advisories as the region remains under a public health emergency, and are coordinating with respective government agencies,” United Airlines said in its response to a Bloomberg query.  Chief Minister Arvind Kejriwal, the leader of Delhi, called the capital a “gas chamber” as thick toxic smog continued to envelop the mega-city of around 20 million people on Sunday. The levels of the deadliest, tiny particulate matter—known as PM 2.5, which lodges deep in a person’s lungs— was at 495 as of 9 a.m. local time Monday, according to a U.S. embassy monitor. The level had soared to 721 as of 1 p.m. Sunday. World Health Organization guidelines suggest levels above 300 are “hazardous.” Customers traveling over the next several days should visit the United Airlines website or download the company’s mobile application for updates, the spokesperson said.