Setting off fireworks to celebrate Chinese New Year may be a centuries-old tradition, but the country's authorities are urging people to light fewer of them this week as cities fight a losing battle against relentless, toxic air pollution.

Dozens of cites in China have outright banned lighting fireworks on Wednesday and Thursday, while others have reduced the number of fireworks vendors allowed to operate.

In Beijing, people received text messages from their phone companies advising against setting off fireworks while local government-run media repeated the warnings in newspapers and on websites.

Still, the state-run China Daily warned Wednesday that Beijing's clear skies would become heavily polluted by the night due to fireworks, reaching the highest level possible on a scale measuring air pollution.