Every 10 days or so Rajabhau Deshmukh buys enough water for his family of six to drink and to irrigate what farmland he can in the drought-stricken Beed district of southern Maharashtra state in India.

Seventy dollars gets him about 2,642 gallons, an allotment that falls so short of his farming needs that five acres of his arid land have grown useless. But for man who makes roughly $600 a year, it’s all Deshmukh can afford.

Across India and much of the globe, the story is the same – the world’s poorest have the most limited access to clean, safe water, and pay the largest chunk of their incomes to obtain it.