Dr. Pramod Karan Sethi, inventor of a low-cost prosthetic foot that has helped millions of people in developing and war-torn countries, has died. He was 80.

Sethi died Sunday of a cardiac arrest in the northern Indian city of Jaipur, his daughter Lata Bhargava said on Tuesday.

Working with a local craftsman, Sethi, a surgeon, developed the Jaipur Foot in 1968 with India’s rural poor in mind.

Since many villagers squat on the ground and spend much of their time barefoot, the limb is designed to be worn without a shoe if need be, and to allow its users to squat. It also allows amputees to pedal bicycles, climb trees and run.

The flexible, low-tech prosthetics are made of plastic pipes, blocks of wood and rubber and strips of leather. Each one costs less than $30.

Indian President Pratibha Patil issued her condolences and said Sethi had “helped amputees to continue their lives without the feeling of inadequacy, for which he shall always be remembered.”

The Jaipur Foot has been used in Afghanistan, Iraq, Cambodia and many other countries, most of them poor and crowded with people who would otherwise be unable to afford prosthetics.

The prosthetic has also been worn by some celebrities, including actress Sudha Chandra, who was wearing a Jaipur Foot when she danced in the 1986 Bollywood movie “Nache Mayuri.”

Sethi wrote in a 2001 essay that when he “tried to work out an acceptable design for our floor-sitting, barefoot-walking culture, the orthodox in the profession viewed this work with derision.

“Because I used traditional craftsmen to give shape to my ideas, I was accused of introducing quackery into our profession and every possible obstacle was put in my way,” he wrote.

Sethi developed the foot with craftsman Ram Chandra, who reportedly had the crucial idea to use rubber after watching a mechanic fix a flat tire. After Sethi won a major international prize in 1981, his relations with Chandra became strained and there is an ongoing dispute over who deserves the credit for the Jaipur Foot.

Chandra still works for a Jaipur clinic that distributes thousands of the prosthetics for free.

Sethi is survived by his wife and four children.