A first batch of "smart manhole covers" featuring anti-theft, shock absorption and noise reduction went on the roads in east China's Hangzhou city on Monday.

Tao Xiaomin from Hangzhou urban management office said the manhole cover's "wisdom" came from an electronic tag.

"When a cover is moved and the tilt angle is greater than 15 degrees, the tag will send an alarm signal to us," Tao said, adding a digital positioning system meant the cover could be located immediately.

Ductile iron is used to make the manhole covers, so their scrap price is very low. Durable rubber rings are also placed under the covers to reduce noise and shock.

A total of 100 smart manhole covers will be in use in the city by the end of April, the office said.