Rohtang Pass is named as such due to people working in bad weather trying to cross d pass. It's a high mountain pass on eastern end of the Pir Panjal Range of Himalayas around 51 km frm Manali. It connects Kullu Valley with d Lahaul and Spiti Valleys of HP, India @Vajiram_IAS
Calcination refers to heating a solid to high temperatures in absence of air or oxygen, generally for the purpose of removing impurities or volatile substances. #UPSC