The council changed its targets for affordable homes in new developments last year following a review of their viability ahead of local development framework preparation.
This resulted in a demand for 25 per cent on brownfield sites and 35 per cent on greenfield sites, but it retained the former 50 per cent target solely for rural sites of between two and 15 homes.
A report this month to a council cabinet meeting noted: "Officers considered it would be inappropriate to continue to pursue a 50 per cent affordable housing target when the council’s own LDF evidence base concluded that this was currently unviable."
It said officers had been obliged to apply the 50 per cent policy "in a pragmatic manner" and that it had "created confusion and has been questioned by the house building industry and local media".
York-based planning consultant Raymond Barnes said: "This policy has meant that either developers have not built at all, or have built a single house, not in multiples of two, because this demand for affordable housing simply isn’t viable.
"There has been a lot of pressure from developers and associated professions in York to get this changed."