* China had planned to launch nationwide scheme in 2017
* But move has faced delays
* NDRC official says will struggle to launch by year-end (Adds detail)
BEIJING, Oct 18 (Reuters) - China will struggle to launch its long-awaited nationwide carbon trading scheme this year as planned, an official from the country's state planner said on Wednesday.
"Although China has collected industrial data for the country, it is very difficult to unify the standards and come up with one for the whole country," Dongming Ren, director of the National Development and Reform Commission's Energy Research Institute told Reuters on the sidelines of a conference.
China, the world's biggest emitter of climate-warming greenhouse gases, has launched seven pilot regional trading schemes and promised to create a national exchange as part of its pledges ahead of the 2015 Paris climate change agreement.
But the national programme, originally touted to launch in the first half of 2017, has faced delays due to unreliable data and other regulatory problems. A government researcher had previously said it would launch by November at the earliest.
(Reporting by Muyu Xu and Josephine Mason; Editing by Joseph Radford)