NEW DELHI - The pollution level in India's capital city has dropped after nearly two weeks, but many areas of Delhi remained in the "very unhealthy" category.
The authorities on Friday rolled back several emergency measures to reduce pollution in the city such as the ban on construction activity and increasing by four-fold parking fares to reduce exhause emissions from private cars.
A new study has meanwhile suggested that the recent surge in Delhi's pollution was caused by a dust storm that blew in from the Arabian Gulf, to the west of Delhi.
The US embassy's Air Quality Index on Friday and Saturday showed air quality remained in the "very unhealthy" category with fine particulate matter level remaining above 200 but less than 300 in most places.
The index had dropped from the hazardous or very severe category that saw levels going beyond 600 in many places.
The severe pollution in Delhi, an annual affair, comes from a combination of the millions of cars on the road, frenetic construction work that adds to the swirling dust, and farmers in the neighbouring states of Punjab and Haryana burning crop stubble after the harvest. The cold winter air then traps the pollutants.
Delhi's population of over 16 million buys 1,400 new cars every day.
A new report from the state run System of Air Quality and Weather Forecasting And Research (SAFAR) has suggested that 40 per cent of the pollution level which resulted in a peak on November 8 was caused by a severe dust storm in the Gulf on October 29.
It affected countries like Saudi Arabia and Kuwait.
The PM 2.5 levels went above 640 micrograms per cubic metre on that date. PM 2.5 is a measure of fine particle matter linked to higher rates of chronic bronchitis, lung cancer and heart disease.
"We have pointed out that on that particular day (Nov 8) there was a peak but the dust storm contributed to pollution for the entire spell. It must have happened across northern and western India but Delhi got highlighted. Now it has gone...'' said Dr Gufran Beig, chief scientist at SAFAR.
The National Green Tribunal on Friday lifted the ban on construction activities, part of emergency measures taken to curb pollution.
The green court has asked authorities to continue with the spraying of water on roads to tamp down the dust. It has also extended the ban on burning of crop stubble, which is a major source of pollution.
The court also asked Delhi to prepare an action plan on controlling pollution and to submit it in the next two weeks. The pollution saw people with respiratory problems rush to hospitals. Others wore masks even while driving their cars.
Schools stopped all outdoor activities with authorities shutting down primary school classes for a week.
But as the annual pollution crisis dissipates, many wondered if the government would be taking any long-term measures to reduce the problem.
"It is very important to have a crisis management action. I don't see the problem going away. It has to be a well thought out action plan, not the knee jerk reaction of shutting closing down school,'' said Ms Ameeta Mulla Wattal, principal of Sprindales School.
She hopes to see during such a crisis more public buses plying the road to reduce the use of private cars and more roads being sprayed with water.
Mr Vikrant Tongad of NGO Social Action for Forest & Environment said the level of urgency in tackling the issue was still missing.
"A lot of work needs to be done. We want a safe level and for that we need time and a lot of measures. At least it should start (tackling pollution). I dont think it has even started.''