Beijing smog
If you live in a big city you already smoke every day
Scientists at Berkeley Earth have taken air pollution levels of major cities and compared them to the effects of smoking.
The alert would remain in place until 1200 GMT on Wednesday, the agency said.
More than 400 cities across China, though, have banned fireworks since last year to curb air pollution during the 15-day holiday and reducing deadly accidents, which are common.
Key areas facing such restrictions are the Beijing-Tianjin-Hebei zone in the country’s north and the Yangtze and Pearl River deltas further south.
Under an orange alert, factories that make furniture, cement and other heavy industry must limit output by between 30 and 50%.
China’s weather bureau warned of visibility of less than 50m in some areas, leading many airports to cancel flights.
The Chinese capital was on the second-highest orange smog alert in the depth of winter.