My guess is that CX has done a deal on those routes the same as they have out of HKG to India (and maybe Bangladesh also) which is that the CX site only sells high fares, and all the discount fares must be bought through a single travel agent (GC Nanda). As I see it this is essentially a corrupt deal where GC Nanda bribed the Indian government for CX to get the traffic rights they wanted and in return CX gave them this exclusive deal. Welcome to Asia!