New Delhi officials have ordered a two-day halt to construction in an attempt to reduce choking pollution that has cloaked the city in smog and dust.

The government's Central Pollution Control Board rated the city's air quality Friday as "severe" - the worst possible category - for the fourth day in a row.

New Delhi's level of PM2.5, tiny particulate matter that can dangerously clog lungs, exceeded 170 Friday morning, more than six times higher than the World Health Organization considers safe.

The New Delhi government has made scattered attempts in recent years to try to control worsening air pollution, including stricter emission norms for cars and a tax on diesel-fueled trucks entering the city. But the pollution has only gotten worse.