While reading about new products related to maintenance, I came across this product, Temperature Labels. These labels could be used to monitor the maximum temperature of any surface where we are investigating causes for over heat. From the product description, it is easy to use and reliable.
In one of my earlier work assignments, while working on reclamation of worn shafts and other machine parts using various welding techniques, we were using a temperature chalk to monitor and temporarily stop the welding process whenever the surface temperature reached the maximum allowed levels of about 300 Deg C. The product depicted in the linked page is an improvement on that application.
Product cost and availability in India are not known.