India faces brutal heatwaves each year, but few places are as punishing as the salt pans of the western state of Gujarat, where tens of thousands of workers endure near-unliveable conditions to keep the industry running.

Up to 50,000 seasonal workers migrate to the remote Little Rann of Kutch region for about eight months, living on the salt flats without electricity, healthcare or permanent shelter. A tanker delivers water for drinking and washing only once every 25 days.

Summer temperatures there routinely exceed 45 degrees Celsius (113 degrees Fahrenheit) and can climb to 47-48C (117-118F). The same dry heat that makes life so harsh also makes the desert ideal for salt production with Gujarat accounting for roughly three-quarters of India’s salt output.

Salt is produced by pumping saline water from bore wells into shallow pans, where it is left to evaporate in the sun and wind. Workers rake the surface daily to ensure even crystallisation, then break and pile the thick crust into mounds.

“We work in staggered timing, … doing our work in early mornings and after sunset,” 42-year-old salt worker Babulal Narayan said. “During the hottest hours, it is too hot to stand.”

With no trees or natural shade, workers build their own shelters: frames of sticks covered with coarse homespun cloth and plastered with wild donkey dung.

“We sit here every two to three hours so that we do not feel weak or dizzy,” 17-year-old Bhavna Rathore said. The dung blocks the sun and lets heat escape while the rough fabric allows some air to pass through, she explained.

Others rely on improvised cooling techniques. Kanchan Narayan, 44, hangs a bottle wrapped in a damp cloth from a string, using evaporation to cool the drinking water. Another worker, Poornima, drinks black tea during the day, saying the hot drink triggers sweating that cools the body in the dry air.

The India Meteorological Department has forecast an “above-normal number of heatwave days” this year in several regions, including Gujarat. At the same time, a shift from costly diesel water pumps to cheaper solar-powered systems has reduced production costs but extended the working season. Work that used to end around March now continues into the hottest months.

The consequences can be deadly. Workers report fatigue, dizziness and nausea, symptoms of heat stress that can lead to organ failure. Studies have found high levels of dehydration, heat stress and early signs of kidney malfunction among salt pan communities.

Unseasonal storms are also adding to the strain. “A big dust storm hit us last month, destroying salt worth 200,000 rupees [$2,100],” Narayan said. He and five relatives earned a profit of about 250,000 rupees ($2,635), roughly $450 each for eight months of labour.

Yet most say they have little choice but to return year after year.

“What else will we do?” 65-year-old worker Rasoda Rathore asked. “We have no land to farm, no livestock to earn our livelihood from. … This is all we know.”