Tons of garbage have been removed from the moat that served as the last line of defense for Chinese emperors since the Ming Dynasty (1368-1644) during a cleanup in Beijing.

More than 4 tons of rubbish, the result of rampant littering by tourists, were removed from the moat surrounding the Forbidden City on Thursday by 40 employees from the Beijing Environment Sanitation Engineering Group Co Ltd.

"It's not easy picking up the trash from the moat as the rubbish is frozen into the ice," said Liu Jialong, a worker from the group.

The rubbish lay in the Tongzi River, the Forbidden City's moat built alongside the Imperial Palace.

Ji Tianbin, deputy head of the Palace Museum, or the Forbidden City, said the museum will set up more trash bins along the moat and put up warning boards to remind the public how to dispose of litter.