BEIJING • Senior Chinese officials have tried tackling their country's chronic air-pollution problem in piecemeal ways - fining some polluting companies, investing in alternative energy sources and ordering lower-level officials to enforce standards, for example.

To the dismay of many, pollution levels remain among the worst in the world, even if some official statistics point to slight improvements.

Now, officials in Hebei province, which surrounds Beijing, have decided to create what they call a "green necklace" of trees in hopes of clearing the air.

Hebei is filled with coal-powered steel factories and has the most polluted cities in China. The pollution from the factories is responsible for much of the smog in Beijing, a city of more than 22 million, and other parts of northern China.

The "green necklace" plan was announced on Thursday on the Hebei provincial government website. The announcement referred to details that appeared in a document on March 15 about coordinating development in Hebei and Beijing.

The plan aims to increase forest coverage on the Hebei-Beijing border, in part by tapping into rivers, reservoirs, wetlands and farmland, an official statement said. Though the plan calls for greater wetlands preservation, it does not mention that Beijing suffers from a chronic drought, so there is very little water on which to draw.

The plan also emphasises the need for "ventilation corridors" that would channel wind and air movement to help disperse smog.

Some environmental experts say the real solution to the pollution crisis around Beijing and Hebei is to shut down significant numbers of steel factories in the region. Powerful official interests and state-owned enterprises have opposed such moves.

NYTIMES