NEW DELHI Bharat Prakash has stayed indoors on Diwali day for the past four years to avoid the smog that envelopes Indian cities during the festival, which celebrates the triumph of good over evil with fireworks and small oil-filled clay lamps.
As the rest of the country celebrates the Festival of Lights, which falls on Wednesday this year, asthma sufferers like Prakash, 22, will be cooped up at home, dreading the blanket of smoke that worsens the already dire air quality.
"I don't step out of the house on Diwali nights," says Prakash, a marketing professional in Pune.
In New Delhi, the morning after Diwali always brings a blanket of thick white smog -- and the situation is getting worse.
A study conducted by the Central Pollution Control Board showed that noise and air pollution levels were higher during Diwali in 2010 than the previous year despite nationwide campaigns against firecrackers.
"It's a concern that pollution levels go up, noise levels go up, and the doctors in cities have also confirmed that hospital admissions during this time increase, due to symptoms related to pollution-related diseases," said Anumita Roychowdhury, at the Center for Science and Environment in New Delhi.
"Every year during Diwali, pollution levels are quite high largely because of the firecrackers, but the traffic intensity also goes up during this time."
Improvements in air quality after Delhi imposed rules making auto-rickshaws and buses run off liquefied natural gas have been partly offset by new cars on the road -- and their numbers have nearly doubled over the last decade, thanks to rising incomes.
Indians are at high risk of respiratory ailments, heart disease and lung cancer, according to recent World Health Organization (WHO) data that showed Delhi's air had almost 10 times the recommended level of PM10 particulate matter, or particles small enough to penetrate to the deepest part of the lungs and cause health problems.
The air in the Indian cities measured ranges between 80 and 251 micrograms per cubic meter of PM10. The WHO recommends not exceeding 20 micrograms per cubic meter. But firecracker-free Diwali campaigns have not been entirely successful, with most revelers looking forward to the noise and lights as part of the festival fun.
Climate and energy campaigner K. Srinivas has a solution.
"If you really want to light up the world with crackers, why not light up with solar lanterns and give them to people, or try to light up a few people's houses, or a few villages," Srinivas said.
"The amount of money that is spent on crackers can easily power a number of houses in rural areas."