Beijing will bolt down all manhole covers to prevent them from being stolen.
Guo Weidong, a spokesman with the Beijing municipal administration commission, said the city will make sure that more than 840,000 covers are securely fastened.
"We have required all companies that have underground pipes to secure their manhole covers before July 20," he said.
The covers have long been the target of thieves who sell them as scrap iron.
Guo said such thefts have been "remarkably" reduced due to heavy penalties and the installation of anti-theft devices.
The commission said the number of cover thefts fell by 3,608 last year. It did not give the total number of such thefts for the year. About 24,000 covers were stolen in 2004.
"Stealing manhole covers is a serious offence, it hinders a city's smooth operation, and threatens people's safety," Guo said.
"The manholes are for the examination and repair of utility installations such as electricity, water, gas and heating."
On June 9, a 4-year-old boy in Changchun, capital of Jilin province, fell down an uncovered manhole and drowned.
Jiang Zhonglian, a member of the 10th National Committee of the Chinese People's Political Consultative Conference, said stealing manhole covers should be considered as endangering public security rather than theft.
"Thieves sell manhole covers to salvage stations and they in turn sell them to the illegal iron foundries," Jiang said.
A manhole cover, which costs 300 yuan ($44), is sold for about 30 yuan to salvage stations, she said.
"They cause such huge risks to people for such a small gain," Jiang said.
In December 2005, a man in Fujian province was sentenced to three years' imprisonment for stealing nine manhole covers.