A Chinese builder buried alive for two hours used Buddhist meditation techniques to control his breathing and survive on just the air trapped in his safety helmet.

Wang Jianxin, 52, should have died within five minutes of being entombed 6ft underground as he worked in a ditch in Ningbo city, eastern China.

But by slowing his breathing he eked out an air pocket in front of his face until rescuers dug him out.

Trapped: Wang Jianxin is freed after two hours buried alive. He used meditation to breathe

Mr Wang said: "I knew the air wouldn't last, so I made myself relax and concentrated on my breathing by meditation.

"It was very still and quiet down there. I was surprised at how easy it was to focus my mind and achieve inner calm, even though I believed I was facing death.

"Later, it became very hot and suffocating. I thought I might not make it back to the surface. Then I heard the sounds of voices and digging, and suddenly I could see again. It was the longest two hours of my life."

A doctor at the scene in Ningbo, eastern China, said: "It's a miracle."

Mr Wang was digging a 15ft ditch at a building site when a wall of earth collapsed, burying him alive.

He said: "I had my back to the wall. I didn't know it was falling until it was on top of me."

Workmates and 11 firefighters dug Mr Wang out.

One said: "As we went deeper, we used our hands to dig as we feared our shovels might injure him. Then we had to hold the soil back with fencing."

It took two hours but finally they pulled out Mr Wang alive from the earth that could have been his muddy grave.

Meditation has a history dating back thousands of years in China.

However, it is a technique more usually associated with Buddhist monks and doctors of traditional Chinese medicine than construction workers. Mr Wang was one of the lucky ones on China's building sites.

The country has a woeful record of safety in the workplace with 101,480 people killed last year in work-related or road accidents, down by about 10 per cent from 2006.

But a glance at any urban building site highlights the sporadic nature of safety measures used by many Chinese companies.

Most workers are given helmets, but in many cases that is the most that employers are willing to provide.

Many of these men are rural migrants who have left their remote patch of farmland in search of better-paying city jobs.

With almost no education and scant notion of safety regulations, they eagerly seize the opportunity of a job and are usually too afraid or too ignorant to demand better equipment from their boss.