A restaurant in eastern China has been caught charging customers an "air cleaning fee" on top of their food bills.

Diners at the eatery in Zhangjiagang city, Jiangsu Province, were charged one yuan ($0.15; 10p) each to cover the cost of purifying the air inside, the official Xinhua news agency reports. Cities in the region have been enveloped in thick smog in recent weeks, with visibility of less than 100m in the worst-hit areas.

The restaurant's owners recently purchased an air filtration system to improve the dining experience, and covered the cost by passing it on to customers without prior warning, the report says.
But after complaints from angry patrons, the local government intervened to stop the practice, telling the owners that it constituted an illegal charge.
A city official tells Xinhua that it wasn't the diners' choice to breathe filtered air, so it could not be sold as a commodity.

While those on the receiving end of the charge were unhappy, the idea has been welcomed by many Chinese social media users. "I'd agree to the fee!" declares one person on the Sina Weibo microblogging site, while another says they would happily pay more for clean air.

One user suggests that the government should follow suit to deal with the country's severe smog problems. But some criticise the way the owners collected the cash. "Paying is not the problem," writes one person. "The problem is being informed in advance and obtaining consent."