Millions of Indians have begun setting off deafening fireworks displays to light up the sky for Diwali, the Hindu Festival of Lights, which celebrates the triumph of good over evil.
People across India also handed out sweets, exchanged greetings with friends and relatives, and adorned their homes with glowing lanterns and oil lamps as they celebrated the country's most important festival of the year.
Diwali marks the return home of the Hindu god Rama from a 14-year exile after killing the demon Ravana, who had abducted his wife, Sita, according to the ancient Hindu epic Ramayana.
A near-constant stream of fireworks and firecrackers lasting until midnight is expected to leave a dark, smoggy cloud lingering for days - a matter of concern for environmentalists.
Mindful of the pollution and the dangers of the deafening displays, authorities pushed this year to cut down on the number of fireworks, and some schools sent notices home urging parents not to buy any.
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The state-run Central Pollution Control Board says it will be monitoring the air quality and noise levels on Sunday night at a dozen locations in New Delhi, India's capital.
SK Tyagi, a senior scientist at the pollution control board, says the noise level at last year's Diwali festival was down from 2011, due mainly to the use of less noisy fireworks.
India's economic downturn appears to have impacted this year's celebrations.
People typically buy gold during Diwali, including jewellery, coins and small statues of the elephant-headed Hindu god Ganesh. But the government has imposed a steep new tax on gold imports, making the already high prices far out of reach for many Indians.
Diwali also is celebrated by Hindus in other parts of the world, including Sri Lanka, Myanmar (Burma), Nepal and Malaysia.
