Heavily pregnant Sonari toils under the burning sun in fields dotted with bright yellow melons in Jacobabad, which last month became the hottest city on Earth.

Her 17-year-old neighbour Waderi, who gave birth a few weeks ago, is back working in temperatures that can exceed 50 degrees Celsius (122 degrees Fahrenheit), with her newborn lying on a blanket in the shade nearby so she can feed him when he cries.

"When the heat is coming and we're pregnant, we feel stressed," said Sonari, who is in her mid-20s.