Fireworks lit up the sky across China on Sunday and straw-hatted farmers in one village hurled molten metal into the air, as the country marked the end of Lunar New Year festivities.

China's Lantern Festival traditionally signals the close of just over two weeks of rest and feasting during the Lunar New Year, the country's biggest holiday, which sees hundreds of millions return to their ancestral homes.

Cities across the country echoed with explosions as millions took to the streets to set off fireworks, and one village hosted a molten metal throwing festival, one of a host of ancient Chinese customs revived in recent decades.

With little more than a straw hat and goggles for protection, a team of farmers spooned molten hot metal from buckets before hurling it at a brick wall, where it rained down in fountains of glowing shards.

The spectacle brought roars of approval from the audience in Nuanquan village, a few hours drive from Beijing, which has revived the centuries-old festival in a bid to boost tourism, building a dedicated amphitheatre for the purpose.

Scrap iron collected from households in the village is melted down in primitive furnaces, which shoot flames and torrents of sparks into the night sky behind the technicolour stage.

Donning a straw hat and a wooly jacket, one 49-year-old maize farmer completed his transition to a fire-thrower, telling AFP: "I love doing it... there's no danger at all."

The fiery festival is said to have been invented over 300 years ago by poor blacksmiths in the village who could not afford the fireworks traditionally used during the season.

"We have an ancient saying, if you don't set off fireworks or throw molten metal... the village won't be peaceful, we still believe that," festival performer Liu Yueqing said, before taking to the stage in a bright yellow uniform.

But the festival was banned during the tumultous decade of the Cultural Revolution from 1966 to 1976. "If you took part, you could be arrested," a local resident surnamed Zou said.

"Anyone who took part was said to be cow monsters and snake demons," he said, referring to a slogan used to condemn people during the period, adding that the revived version of the festival was "bigger and better than ever".

Faced with low profits from farming, villages across China have turned to tourism as a source of income, rediscovering their ancient architecture, crafts and festivals as a way of luring visitors from the cities.

Some taking in the sites at Nuanquan were worried by the tourism push. "Now the biggest threat to traditional village culture isn't politics -- it's economics," Hou Xue, a Beijing cultural relic enthusiast said.

"These flashy government organised events don't have the right flavour, they don't seem authentic," he added.

While hot metal sparks fizzed under the full moon, others in China set off fireworks and ate sweet dumplings to mark the festival.

"The pork ones sold out early. We can't make enough," said a clerk at a branch of a famous dumpling chain in China's commercial hub of Shanghai, who offered crab meat or sweet sesame paste alternatives.

Worshippers thronged Shanghai's Jing'an Buddhist Temple, burning incense and tossing coins into a giant urn to make wishes for the coming year.

A "fireworks spree" on Sunday evening led to Beijing's air quality falling to hazardous levels, the state-run China Radio International reported.

Parts of the country have been blanketed with thick smog in recent weeks, with the pollution blamed on coal-burning and auto exhaust emissions.

Many of China's migrant workers living in rural areas delay their return to their workplaces beyond the official public holiday, which lasts only a week.