Some six million students lost up to two weeks' worth of classroom learning last year as temperatures hit a record 38.8 degrees Celsius (101.4 degrees Fahrenheit), according to the education department.

Schools reported cases of heat exhaustion, nose bleeds and hospitalisations as students struggled through lessons in classrooms without air conditioning.

Scientists say that extreme heat is a clear marker of climate change, caused largely by burning fossil fuels like coal, oil and gas.

Last year's heat was further exacerbated by the seasonal El Nino phenomenon.