By Alan Johnston
BBC News, Delhi
People in Delhi can barely see the sun through the smog
For days the Indian capital, Delhi, has been shrouded in a blanket of smog that has put the city's dreaded pollution problems back in the news.
"Smoggy days are here again," read a front page headline in one paper. "Smog is back with a vengeance," said the Times of India.
Look out over the capital and you see trees and tower blocks starting to disappear into the lingering grey mist or haze.
It is as if Delhiites have been living through a perpetual fog, which the sun only penetrates in a weak and wintry way.
By the end of the day you can almost taste the pollution in the air. And all over the city people are snuffling and coughing, and blaming it on the smog.
There's a widespread sense that the city is losing ground in its anti-pollution battle.
Dr Sanjeev Bagai of Rockland Hospital said that there had been a 30% increase in the number of complaints from people with respiratory difficulties.
Delhi resident Chepuri Shri Krishna says people are suffering
"It's too much, it's just getting unbearable," said Chepuri Shri Krishna, as he went about his business on KG Marg, one of city's major avenues.
"And you can see the consequences. A lot of people are suffering from asthma and breathing problems."
Much of the blame for the smog is laid on the ever growing torrent of traffic that streams through the city.
As India boomed economically in recent years hundreds of new cars were being registered in Delhi every day.
The government has made huge efforts to tackle the pollution problem.
Eight years ago all buses, taxis and rickshaws were switched over to ecologically friendly fuel - compressed natural gas.
And the government's Pollution Control Board claims to have made substantial progress. It says that carbon monoxide levels are down by 50%, and that the amount of sulphur monoxide in the air has been cut by nearly three-quarters.
The independent environmental watchdog, the Centre for Science and Environment (CSE), agrees that these figures are correct on average across the year.
But a CSE spokesman said that under certain climatic conditions in the winter months there can be a build-up of pollutants.
And he said that while overall levels of gasses like carbon monoxide had fallen, the amount of dust, petrol and diesel matter in the air had been on the rise for the past three years.
On windless, winter days this "particulate matter" can combine to cause serious problems.
The spokesman said that the authorities had to work to continually think of new ways to combat the pollution menace.
He said that improvements to public transport were very much needed.
And he also called for better methods of alerting people to air quality problems, enabling those with respiratory difficulties to steer clear of the worst affected parts of the city.