PHOTOS: Delhi chokes on thick smog

The air quality index -- a measure of the level of pollutants in the air -- shot past 400 in many places in Delhi the second time since Diwali and potentially signalled the start of Delhi’s notoriously toxic winter.

Below are some images to show just how bad the situation is in the national capital. 

A thick haze blanketed the city as pollution levels breached permissible standards by multiple times. Photograph: Saumya Khandelwal/Reuters

The low visibility also affected flights and trains in the capital. At lease 20 flights were either delayed or affected after foggy condition prompted Delhi airport authorities to close the runway. Photograph: Kamal Kishore/PTI Photo

WATCH: DELHI ENVELOPED IN A BLANKET OF SMOG

Officials at the weather department said the weather was expected to remain cloudy for the next two to three days and the temperature to fall further, suggesting any immediate respite from the prevailing conditions was unlikely. Photograph: PTI Photo

The Indian Medical Association also issued a stern warning on potential health hazards, describing Delhi as a “public health emergency state”. Photograph: Saumya Khandelwal/Reuters

It's a wonder how people drove to work in the national capital as visibility was at 200 metre resulting in slow traffic. Photograph: Cathal McNaughton/Reuters

A man, wearing an anti-pollution mask, jogs throgh smog at Lodhi Garden in New Delhi. Photograph: Kamal Kishore/PTI Photo

Delhiites do yoga in Lodhi Gardens. If the situation deteriorates and persists for at least 48 hours, schools will be asked to remain close and the odd-even car rationing scheme will kick in. Photograph: Kamal Singh/PTI Photo

A traffic policeman discharges his duty as India Gate is enveloped in dense smog, in New Delhi. People in Delhi may have to pay four times the usual parking fees with a Supreme Court-appointed panel recommending emergency measures to tackle severe pollution levels. Photograph: Manvender Vashist/PTI Photo

A traffic policeman wears anti-pollution mask to protect himself from growing level of air pollution, in New Delhi. Photograph: Manvender Vashist/PTI Photo

A smogged out Lodhi gardens. Photograph: PTI Photo