Children armed with whistles will soon be patrolling villages in central India to try to shame those defecating in the open, a report said Sunday.

Madhya Pradesh state government is expected soon to launch the unusual sanitation initiative, in which schoolchildren will blow their whistles loudly when they spot someone squatting in the open instead of using a toilet.

Open defecation has long been a major health and sanitation problem in India, with Prime Minister Narendra Modi saying every household should have a toilet within four years.

But a Madhya Pradesh official said many preferred to relieve themselves in the open rather than use a toilet, requiring unusual efforts to halt the practice which spreads disease.

“It is not just enough to make ‘pucca’ (proper) toilets to stop the practice of open defecation in rural areas,” Sanjay Dubey, a divisional commissioner for Indore region, told the Press Trust of India (PTI).

“There is also a need to launch an effective social drive in such areas to check it,” Dubey said.

Children in the Indore region will be educated about the need to keep their surroundings clean, before being handed the whistles and asked to roam their neighbourhoods, he told the news agency.

“This (blowing a whistle) would make that person feel shameful and would help to check this practice.”

Modi has stressed the need to clean up India, which has a reputation for poor public hygiene and rudimentary sanitation.

A recent report by the UN children’s fund UNICEF estimates almost 594 million — or nearly 50 percent of India’s population — defecate in the open.