IGST rates for construction services: reduced rates with strict input tax credit limits, reverse charge obligations and election options. Notification prescribes IGST rates and conditional qualifications for inter State services, with a layered regime for construction and real estate services that distinguishes affordable, residential, commercial and other construction activities; mandates limited input tax credit eligibility and project wise computation of ITC adjustments (Tx = T - Te) under Annexures I and II using carpet area, percentage invoicing and percentage completion; requires promoters to procure at least 80% of inputs from registered suppliers or face reverse charge on shortfalls (with special treatment for cement); and provides one time option and procedural forms for electing alternate project rates and for GTAs and hotel premises declarations.