By Nils Blythe
Business correspondent, BBC News, Shanxi, China
Nils Blythe has travelled to one of China's main coal producing region to look at how the country is tackling global warming.
China has the world's biggest coal industry - and most pollution
"Shanxi province is the worst for pollution", says local businessman Sung Shue Fung.
"When you are driving you often can't see clearly in front of you. A lot of accidents happen because people can't see."
Shanxi is China's main coal-producing region. And this is a country which mines and produces far more coal than any other nation on earth.
Much of it is used in power stations to generate the electricity which is fuelling China's remarkable industrial revolution. And China is expected to go on opening new coal fired power stations at the rate of about one a week for years to come.
Poor air quality
While I was in Shanxi province the air quality was poor all the time. Enough to make the eyes smart and leave a bad taste in the mouth. And local stories of the worst days abound - the days when cars drive with their lights on at lunchtime.
China is building one new power station each week
The pollution poses serious health problems for local people.
And it's an issue which the rest of the world needs to take seriously.
Because as well as the gases which affect the local air quality, coal burning also produces carbon dioxide, a greenhouse gas which contributes to climate change.
China is expected to overtake America in the next few years as the world's single largest emitter of carbon dioxide.
For the moment, reducing carbon dioxide emissions is not China's top priority.
But there is growing concern in the country about local air quality - the pollution which I, literally, tasted in Shanxi province.
Official regulations require new power stations to have filtering equipment to remove the particulates, sulphur and nitrous oxide which damage local air quality.
Local campaigners question whether power station owners always turn on the filtering equipment.
But air pollution caused by coal-burning was a huge problem in Britain in the middle of the twentieth century and has been dramatically reduced.
It is possible to be optimistic that as internal pressure mounts for better air quality, China will reduce the pollution in its big cities. Beijing - although still polluted - has taken some major steps to improve the air in time for the Olympics.
China's big dilemma is what to do about carbon dioxide and other greenhouse gases.
It has plentiful supplies of coal for the future.
But coal-burning power stations produce more carbon dioxide than gas-fired plants.
And China - which already has severe problems with water supplies in many cities - has a lot to lose from global warming.
There may be a technological resolution to the dilemma.
Experts argue that it should be possible to remove carbon dioxide from power station emissions and bury it deep underground.
Research is being carried out in Beijing at the Tsinghua-BP clean energy centre in Beijing.
Professor Ni Wei-Dou is one of the leaders of the research programme. And he argues that it will eventually be possible to use coal as a 'de-carbonised fuel'.
But there are formidable obstacles to all the plans for so-called 'carbon sequestration'. Some are technical.
Storing carbon underground for centuries requires very specific geological formations - interest is focussing on areas where oil and gas has been extracted.
West should take the lead
Some of the obstacles are political and economic.
At the moment, even the proponents of carbon sequestration admit that it would add substantially to the cost of energy production.
And that raises the question of which countries will pioneer the technology.
Dr Mike Farley is director of Technology Policy Liaison for Doosan Babcock, a company which builds power stations in China and around the world.
He argues that while there are lots of plans for carbon neutral coal-fired power stations, they are not getting the active support from governments that they need. He looks to highly developed countries like Britain to take a lead.
In places like Shanxi province, China's dependence on coal is all too evident.
But - like the carbon dioxide it produces - responsibility for developing the technology which could make coal a sustainable energy source spreads around the world.
Nils Blythe's report from China's Shanxi province was broadcast on BBC Radio 4's PM programme on Wednesday 14th February 2007.