NEW DELHI • The Indian capital declared a pollution emergency yesterday as toxic smog hung over the city for a third day and air quality worsened by the hour.
Illegal crop burning in the farm states surrounding New Delhi, vehicle exhaust emissions in a city with limited public transport, as well as swirling construction dust have led to the smog, which arises every year.
The problem has been compounded this year by still-weather conditions, the weather office said.
In neighbouring Pakistan's second largest city of Lahore, near the Indian border, hundreds flocked to hospitals seeking treatment for respiratory illnesses and eye infections caused by the pollution.
The PakAirQuality network, which publishes unofficial air reports on social media, said the concentration of PM2.5 in the city had topped 300. The safe limit is 50.
In New Delhi, the United States Embassy's PM2.5 measure showed a reading of 608 at 10am, and a reading of 591 an hour before.
PM2.5 refers to particulate matter about 30 times finer than a strand of human hair. The particles can be inhaled deep into the lungs, causing heart attacks, strokes, lung cancer and respiratory diseases.
Residents complained of head-aches, coughs and smarting eyes.
"Waking up with a headache, breathlessness and throat irritation every day," social media user Bhavani Giddu wrote on Twitter.
Many people stayed at home and restaurants in some of the city's most crowded parts were deserted.
"I'd like to assure people that the central government shall do everything possible to bring about an improvement in air quality in Delhi and the national capital region," Federal Environment Minister Harsh Vardhan said as the authorities faced criticism for failing to take steps to fight a yearly problem.
The haze covered India Gate, a war memorial in the centre of the city where Britain's Prince Charles and his wife Camilla paid their respects yesterday.
The city will curb car use next week, the state government said, in the latest attempt to bring about cleaner air.
New Delhi will follow an "odd-even" scheme for five days starting Monday, in which cars will be allowed on the roads based on whether their number plates carry odd or even numbers.
"It is an emergency situation," said Delhi Transport Minister Kailash Gahlot.
In other measures, commercial trucks have been banned from the city unless they are carrying essential commodities, all construction has been stopped and car parking charges have been raised four times to force residents to use public transport. Schools have been shut for the week.