It's 63C (145F) deep inside 's vast manufacturing site in Bharuch, western India, where 1,000 tons of molten glass a day is pressed through glowing furnaces into flawless, paper-thin sheets that will eventually form solar panels.
Three female staff stationed on a gantry above one of the sweltering manufacturing lines peer down to scan for the smallest of imperfections, using a long wooden stick topped with an ink-soaked cloth to mark any defects. The workers are an additional layer of defense, adding to checks being made remotely through a bank of cameras.