Shanghai residents who go to the effort of sorting their trash for a city trial have been left bemused to see garbage collectors mix it all together again, a legislator said yesterday.

City officials admitted that the pilot program, which aims to cover 1,000 communities by end of the year, has been stymied by a lack of facilities and qualified staff.

"Residents who responded to the call and sorted their garbage told us they were unhappy to see the waste was later just mixed in again, and started to question the point of their efforts," said Zhang Wuping, a legislator who joined an investigation into the program.

Only 475 neighborhoods have become involved since the program began in May, and it's unlikely the city government will achieve its target by the end of the year, said the local greenery bureau.

The initiative is part of efforts to reduce the city's domestic waste and realize more environmentally friendly garbage treatment.

Under it, the authorities encourage householders to sort their garbage.

Lu Yuexing, deputy director with the greenery bureau, said the garbage treatment capacity for the sorted waste is too small and there are not enough trained personnel.

The official admitted that in some neighborhoods sorted waste was mixed in again in collector trucks because the processing facilities were not yet ready.

Lu said local authorities would cooperate to speed up getting staff and facilities in place.

Meanwhile, plans to raise the city's overall garbage treatment capacity are already under way, Lu said.

Over the next two to three years, the local government plans to build a batch of new processing plants in suburban districts.

These will use the latest technology to minimize their influence on the environment, officials said.

And the city plans to complete a network to support domestic garbage sorting by 2015, covering most downtown neighborhoods.

At present, more than 70 percent of local daily garbage is processed at the Laogang landfill compound.

People living in nearby villages believe it emits toxic fumes as many of them suffer from ailments including skin conditions, respiratory diseases and cancer, that they attribute to the plant.