BEIJING (Reuters) -Half of all vehicles sold in China in July were either new pure electric vehicles or plug-in hybrids, industry data showed, a milestone that underscores how far the world's biggest auto market has leapt ahead of Western counterparts in EV adoption.

Sales of so-called new energy vehicles (NEVs) jumped 37% last month from the same period a year earlier, accounting for a record 50.7% of car sales, data from the China Passenger Car Association showed.

That pace of growth for NEVs accelerated from a 28.6% surge in June. Sales of pure electric vehicles climbed 14.3% in July, up from 9.9% growth for June.

But overall domestic car sales fell 3.1%, extending declines for a fourth straight month with consumer confidence weak as the economy struggles to gain momentum amid a prolonged crisis in the property market.

Weakness in the auto market prompted China's state planning agency to announce in late July that cash subsidies for vehicle purchases would be doubled - up to 20,000 yuan ($2,785) per purchase - and would be retroactive to April when the subsidies were first introduced.

Additionally, some cities with curbs on car purchases have moved to relax restrictions. The capital city of Beijing, for instance, announced last month it would offer to expand its NEV license quota by 20,000, the first easing of curbs since a strict quota system was put in place in 2011 to ease traffic congestion and improve air quality.

($1 = 7.1838 Chinese yuan)