NEW DELHI: An Indian government scientist says air quality in New Delhi has worsened this week and is now "very poor."

Gurfan Baig of the state-run Indian Institute of Tropical Meteorology said Friday that levels of tiny particulate known as PM 2.5, which can penetrate deep into the lungs, had reached 250 micrograms per cubic meter in various neighborhoods in and around the Indian capital.

The amount is more than 10 times higher than World Health Organization safety levels over a 24-hour period. Although the level is threatening to the health, it is still much better than Beijing recently, where levels of PM 2.5 have been hovering around 500.

Fine particles come from combustion made by motor vehicles, power plants, wood fires and some industrial processes.