![](http://www.ecns.cn/hd/2023/08/15/a452b014437a40bf89b13d04a681093c.jpg)
Archaeologists work at an excavation site in the Pingliangtai Ancient City ruins in central China's Henan Province. (Photo provided to China News Service)
A number of pottery drain pipes at a Neolithic site of Longshan Culture dating back more than 4,000 years has been discovered in Henan. It is China's earliest and most complete urban drainage system.
![](http://www.ecns.cn/hd/2023/08/15/1f9ba1b0d7ea4da59064d22158a137a4.jpg)
A graphic of the excavation site in the Pingliangtai Ancient City ruins in central China's Henan Province. (Photo provided to China News Service)
![](http://www.ecns.cn/hd/2023/08/15/72b6b038300f4e0a88d79a80c2c82a5e.jpg)
A graphic of the excavation site in the Pingliangtai Ancient City ruins in central China's Henan Province. (Photo provided to China News Service)
![](http://www.ecns.cn/hd/2023/08/15/2425c34cd8a940adae902705c94bdfe9.jpg)
Pottery drain pipes are excavated in the Pingliangtai Ancient City ruins in central China's Henan Province. (Photo provided to China News Service)