Hundreds of “manual scavengers” die each year cleaning out sewers in cities across India but a machine unveiled for Monday’s World Toilet Day could help to end that tragic record.

Thousands of mostly low-caste Indians are employed in one of the world’s dirtiest jobs unclogging human waste from underground pipes.

More than 1,300 have died, mainly suffocated, in the past three years, according to the Sulabh International charity.

The men are called “manual scavengers” because they mainly scrape the waste with their bare hands without any protective gear or masks.

The machine launched by Sulabh injects high pressure water into the tunnels and tanks and then collects the waste with a mechanical bucket operated from ground level.

A remote control inspection camera generates high-resolution images of the sewer system.

Bindeshwar Pathak, the Sulabh International founder, said that forcing humans into the sewers was “demeaning”.

“We hear so often the tragic news about sewer workers losing their lives,” he said.

“This machine can safely clean the waste matter and it will gradually make manual scavenging redundant.

“With this machine we hope no person will die in the sewers any more.”

Indian lawmakers have passed several laws aiming to stamp out the age-old practice of manual scavenging, the latest in 2013. But many scavengers are still used through subcontractors.

In rural areas, women “scavengers” clean out primitive non-flush toilets with basic tools, although the practice is now on the wane.

Pathak also unveiled a giant Indian-style toilet pot to raise awareness about sanitation in a country where some 150 million people do not have home toilets.