Disney’s soon-to-open Magic Kingdom in Shanghai might lose some of its sparkle as China’s notorious smog problem threatens to snuff out the park’s signature closing fireworks show.

A new regional fire services rule that took effect at the beginning of this year says all fireworks shows will be prohibited in Shanghai without exception on “heavily polluted days."

According to a notice posted on its website, the local government defines “heavily polluted days” as days when the air quality index is above 200 on China's 500-point scale.

Shanghai suffered 8 heavily polluted days in 2015, according to the local environmental protection bureau’s database.

It isn't clear whether the local authorities might treat the “happiest place on earth” with mercy on polluted days, considering the government’s previous offers of unusual extra attention and efforts to support Shanghai Disneyland, the first Disney theme park to open in mainland China.

A local newspaper affiliated with Shanghai’s party-controlled Jiefang Daily Group quoted the chairman of Shanghai Shendi Group -- a joint venture between Walt Disney Co. and the Shanghai government -- as saying the theme park is located outside Shanghai's outer ring and therefore isn't restricted by the firework ban on normal days, without explaining what that meant.

The chairman, Fan Xiping, also said that the theme park will minimize the pyrotechnic extravaganza's influence on the local environment by using advanced and environmentally-friendly fireworks.

Mr. Fan could not be reached for confirmation on Tuesday.

A Disney spokeswoman said in an e-mail that the company "had a long-standing record and commitment to fireworks shows and technologies that were uniquely entertaining and environmentally friendly." She added that Disney has been working closely with all government authorities and would strictly comply with all local regulations.

Calls to the Shanghai fire department went unanswered.

Major Chinese cities like Beijing and Shanghai are struggling to fight smog -- yet doing so presents them with the dilemma of sacrificing economic activity for the sake of air quality as the country's growth is slowing down.

This week, the Shanghai government set a goal of decreasing the average daily density of PM2.5 particles, a major contributor to air pollution, to 42 micrograms per cubic meter by 2020, from 53 last year.

The World Health Organization sets a safe level of PM2.5 exposure at 25 micrograms per cubic meter over a 24-hour period.

--Yang Jie, with contributions from James T. Areddy.