The chalk mark is still in action in CCU, they screen the luggage before it comes to the belt. BOM has the chalk mark last year the (multiple) whiskey bottles I had in the checked luggage for my father were detected and chalk marked. Xray before leaving the baggage area is deployed off and on in BOM&DEL depending on what flights arrive and how greedy the customs gets. They usually go for fleecing the migrant laborers (GCC flights) or the traders (BKK flights).