NEW DELHI — Think twice before taking a deep breath in New Delhi, where worsening air pollution has drawn comparisons with Beijing, the world’s pollution poster child.
On bad days in India’s capital, the air is so murky it slows traffic to a crawl. Conversations are punctuated with rasping coughs. Weak bands of sunlight filter through a grainy sky.
Sensors have routinely registered levels of airborne particles at hazardous levels in recent months — three to four times New Delhi’s sanctioned limit, rivaling Beijing’s levels.
While it’s uncertain which city has worse smog, one thing is clear: China’s capital is taking steps to improve air quality but New Delhi hasn’t done much, largely because there’s been little public outcry.
Doctors overwhelmingly agree that more people in New Delhi are getting sick from air pollution, but there are scant data to show it.
‘‘It seems incredible that the politicians and judges living in Delhi would not be worried about how their families and children are suffering from the bad air,’’ said Dr. K. Srinath Reddy, head of the Public Health Foundation of India. ‘‘People have to recognize the extent of the damage happening. That’s where the outrage will come in. That’s when the action will happen.’’
This week, Reddy cochaired the first meeting of a new Health Ministry committee tasked with recommending ways to protect the public. A report is due in a year.
There are various ways to measure pollution, but comparisons have generally focused on the particulate matter, sometimes called soot.
In New Delhi, levels of PM 10 — particulate matter that is 10 micrometers in size — have been about 400 micrograms per cubic meter in the past several months, four times the city’s limit and well above the World Health Organization’s recommended limit of 20. In 2011, the average rose to about 280.
In Beijing, average annual PM 10 levels declined to just above 100 last year, according to the Center for Science and Environment, a Delhi group.
Beijing’s alert system advises caution on smoggy days, and the term PM 2.5 — particles even smaller than PM 10 and considered more dangerous — has become part of the vocabulary among citizens, with many checking smartphone apps for hourly readings. During high alert times, schools may be closed, industries shut down, and government vehicles taken off the roads.
New Delhi has no such alert system or emergency protocols.
Beijing has also launched control measures, from limiting the number of cars to punishing factories that fail environmental standards.