The term "hutong", originally meaning "water well", came from the Mongolian language about 700 years ago.
The implication was that where there was a well, there were residents.
Future wells dug deep enough, to the low - arsenic part of the aquifer, could help.
After arsenic, the most important of these is manganese, which exceeded World Health Organization guidelines in 44% of the wells.
Rice fields filter arsenic from the water, so wells under those fields could also be part of an answer to a problem affecting millions of Bangladeshis.
There was only one way to find out if water from a groundwater well contains arsenic and that was by sampling and analysing the groundwater — a time-consuming a nd costly matter.
Discovered in 1974 when a local farmer was digging a well, the terracotta army, buried in 210 BC with the first emporer of the Qin dynasty, is a breathtaking site.
If the water you are using comes from a well or water source that is not treated with chlorine, add two drops of non- scented liquid household chlorine bleach to each gallon of water.
Here a child in Nepal drinks from a well containing water contaminated with arsenic, which can lead to abnormal heart beat, blood vessel damage and cancer, among other ill effects.
Now all we can do is go over to a neighbour who has a borehole.