Answer:
Around the world the most significant restriction on access to potable water is money. While access to raw water sources, clean or otherwise, is important, the purification process itself is expensive. Once water has been rendered potable, it is important that it be delivered without reintroducing contamination.
Why Farmland is Abandoned:
As groundwater pumping increased, water tables dropped, requiring pumping from deeper levels and at greater costs. Because of the increased cost, irrigation became prohibitively expensive. Farms thus were abandoned as unprofitable, especially in Cochise and Pinal counties.
Answer:
The Soviet Union under Joseph Stalin and The People's Republic of China with Mao Zedong
Explanation:
It's on Britannica
