MUMBAI (Thomson Reuters Foundation) - The Indian government has rejected criticism of its ambitious sanitation program by a United Nations official who said lower-caste communities had their rights violated by being left to clean toilets built in a nationwide drive.

Prime Minister Narendra Modi launched the Swachh Bharat Abhiyan, or Clean India Mission, with much fanfare after he took office in 2014. The main aim is to eliminate open defecation by October 2019 by building individual and public toilets.

But activists say the campaign has failed to end the practice of manual scavenging, or clearing faeces by hand, and has even exacerbated the problem because the toilets are not connected to water supplies or the sewage system.

The U.N. special rapporteur on the human rights to safe drinking water and sanitation affirmed those observations.

The emphasis on building toilets should not “contribute to violating fundamental rights of others, such as those engaged in manual scavenging, or ethnic minorities and people living in remote rural areas,” Léo Heller said in a statement on Friday.

“Eliminating open defecation is not only about building latrines, but requires adequate methods for behavior change, and sufficient water supply is a pre-requisite for the sustainable and safe use of adequate, low-cost latrines.”

The Indian government dismissed Heller’s “sweeping judgments” as “either factually incorrect, based on incomplete information, or grossly misrepresent (ing) the situation”.

The campaign fully conforms to human rights principles established by the U.N., it said in a statement, adding that it “strongly rejected his mostly baseless assertions”.

Despite laws to end the practice of manual scavenging, a euphemism for clearing faeces from dry toilets and open drains by hand, it is prevalent in many Indian states.

The occupation has long been thrust upon the Dalit community, the lowest ranked in India’s caste system.

At least 90 percent of the country’s estimated one million manual scavengers are women, who clean public and private dry latrines with barely any safety equipment.

While caste-based discrimination was banned in 1955, Dalit communities continue to face threats of violence if they try to give up manual scavenging.

Dozens of manual scavengers have died in recent years from toxic fumes in septic tanks, activists say.

The Indian government has shown “unprecedented commitment” in tackling the gaps in sanitation, but it also needs to adopt a humanitarian focus in addressing the issues, said Heller, who will submit a full report of his findings in September 2018.