Taiwan's annual ghost festival is clashing head on with the environment and the ghosts are holding their own.

Concerned about rising air pollution, authorities on this island of 23 million people have encouraged residents to turn their backs on the centuries-old tradition of burning mock paper money to appease thousands of restless spirits, and pay their respects on the Internet instead.

This year's festival began on July 25. Chinese tradition holds that the gates of the nether world open once a year and ghosts walk the earth freely for 30 days. Those who entertain them well — showing their obeisance by burning paper money — are assured a year of peace and prosperity.

But with an estimated 100,000 tons of the stuff immolated every year — a significant portion during ghost month — Taiwanese authorities are worried about environmental damage.

"Ghost month celebrations are a good tradition, but burning stacks of paper money outdoors could worsen air pollution and create toxic or cancer-inducing particles," said Lin Chien-chai, an Environmental Protection Bureau official.

This year several local governments took the EPB warnings to heart and set up Web sites allowing people to pay their respects to ghosts in virtual Buddhist temples — even providing them with a printed worship certificate attesting to their devotion.

"The important thing is to pay true respect from your heart," intoned the site of the municipal government in Kaohsiung, Taiwan's second largest city.

But old habits die hard, and in downtown Taipei money burning was in full swing, with worshippers giving short shrift to the Internet option.

Chen Ching-yun, manager of an insurance firm, carried a thick stack of brown-colored bills together with apples, bananas and star fruit and placed them on a table in the lobby of a shiny office building as part of his obeisance.

"Our salespeople run their errands on cars or motorcycles every day, and I'll pray they have peace and stay away from accidents on the road," he said.

Betty Chang, owner of a nearby boutique, said she observed the ghost festival every year and that the idea of paying her respects via the Internet had never occurred to her.

"I put in a lot of effort in the business and work long hours, and I pray that nothing will go wrong," she said.

The mass circulation United Daily News identified Transportation Ministry workers as among the most zealous ghost worshippers.

"They will pray to have fewer plane crashes and traffic accidents," the newspaper reported. "Officials will also pay respect to the ghosts whose tombs were knocked down to make way for new bridges and roads."

But some younger Taiwanese are embracing worship on the Internet instead — particularly on Web sites that mix fealty and fun.

One is the Silverway, a site that makes ghosts into playful cartoon characters, and offers a variety of prescriptions for getting rid of them.

"If you cannot accumulate a fortune despite your hard work, drive your ghost away," the site proposes. "If you haven't gotten a raise in 10 years, leave it to us to put that ghost behind you."