India, Nov. 3 -- Most of us confuse toilets with sanitation. What happens after we flush or pour water, where the waste goes and how it is treated, rarely crosses our minds. But this process is turning into an environmental and public health crisis in Uttar Pradesh, India's most populous state. Even as the state celebrates 100 per cent toilet coverage under Swachh Bharat Mission (Urban), the downstream systems to handle faecal sludge remain neglected.

Across more than 700 towns, Uttar Pradesh has constructed over 50 faecal sludge treatment plants (FSTPs) and co-treatment facilities to safely manage waste from septic tanks and non-sewered toilets. An FSTP treats waste collected from on-site sanitation systems such as pit latrines and sept...