Water stagnating at a construction site. A dwindling number of mangroves along the shore. Lakes choked with algae and hyacinth. Sewage pipes leaking into the sea.

These are common sights in India.

Until recently, the best people could do to try to draw attention to such problems was to tweet pictures to the government or write letters to the newspaper — hoping someone with the power to make changes would take note.

Increasingly, scientists and activists are enabling citizen observers to collect data and upload it to the cloud with the aim of pushing all stakeholders — government agencies, corporations and citizens — toward change. One of the United Nations’ Sustainable Development Goals is free, drinkable water for all by 2030.