Even as temperatures soar in the north, making it necessary to stay indoors, a small band of healthcare activists has been setting out each day in the blazing sun to help rehabilitate people afflicted with arsenic poisoning in villages of eastern Uttar Pradesh.

The Inner Voice Foundation’s small team has reached out to 50 villages and perhaps 50,000 people so far this summer, says Saurabh Singh, who leads the organization and describes himself as a homegrown arsenic mitigation expert.