Problems arose this morning at flights and train schedules in the capital of India, New Delhi, as dense fog covered the area, reducing visibility to just 50 meters in some areas.

“Very dense fog” was seen in the city, where the temperature was just 9 degrees Celsius, the India Meteorological Department said, adding that “dense to very dense” fog was likely in the early hours of the day in some areas until tomorrow, wednesday

The “dense haze” contains particulate matter and other pollutants, according to the weather service, which warned of the impact it could have on the health of the city’s 20 million residents.

The ambient air quality index in New Delhi this morning stood at 376, which is classified as “very poor”, according to the website of the Central Pollution Control Board. A good level is considered a value between 0 and 50.

Dense fog caused delays to at least 30 flights scheduled to land or depart from the Indian capital’s airport, according to Indian news agency ANI. About 14 trains plying in North India were also affected, ANI reported.