Start here when a site is in an HSIIDC township or estate: layout plans, availability and allotment rates are published by HSIIDC. Treat any figure as current only for the date you read it.
Library
HSIIDC — Industrial Model Townships and estates (official pages)
HSIIDC's pages for its Industrial Model Townships (including Manesar, Bawal and Kharkhoda), industrial estates, layout plans, and rates of allotment.