KUALA LUMPUR, Malaysia — For much of the year, the Petronas Towers, the world’s tallest twin buildings, are gleaming landmarks visible far from the city center here. But last weekend, the 88-story structures were shrouded in a smoky haze that prompted doctors to warn people with respiratory problems to wear masks.
The haze, attributed mostly to fires burning on the Indonesian island of Sumatra, has become a recurring summer blight, engulfing parts of Malaysia, Thailand, Brunei and Singapore, and leaving a litany of health and economic costs in its wake.
Experts say that some progress has been made in the 15 years since the Association of Southeast Asian Nations first pledged to combat the problem, after one of the worst forest fires in the region’s history. That fire was traced to the clearing of land by burning in Indonesia.
专家说，15年前印尼因烧荒而引发了该地区史上最严重的森林火灾，当时东南亚国家联盟（Association of Southeast Asian Nations）第一次承诺解决这一问题，自此之后，情况确实有所改善。
But experts say far more must be done before the area will see clearer skies, including better law enforcement and international cooperation.
The haze that hit Kuala Lumpur last weekend was the worst so far this year, according to Halimah Hassan, director general of Malaysia’s Department of Environment, with readings on the air pollution index exceeding the threshold for unhealthy.
马来西亚环境部（Malaysia’s Department of Environment）部长哈莉玛·哈森（Halimah Hassan)表示，上周末侵袭吉隆坡的阴霾是今年以来最严重的，空气污染指数超过了不健康指数界限。
By Monday, winds had begun pushing the haze north. Asean’s Web site on the haze reported that the smoke was also affecting southern Thailand early last week.
The skies over Kuala Lumpur were clearer on Friday, and pollution levels in the capital had dropped to mostly moderate levels. But unhealthy levels were reported in Miri, in Sarawak State, on the island of Borneo, because of a peat fire that started in the area on Thursday.
Ms. Halimah warned that the haze could continue to be a problem in the coming months, given predictions of dry weather and southwesterly winds until September.
The environment department has imposed a blanket ban on open fires in Malaysia and has increased efforts to control local sources of air pollution. However, Ms. Halimah said, fires in Indonesia were primarily responsible for pushing the air pollution index to unhealthy levels.
A major source of smoke, researchers say, are fires set on palm oil and rubber plantations, primarily in Sumatra, to get rid of old trees and to clear land for new plantations.
The 1997 forest fires in Indonesia smothered Southeast Asia in its worst haze in decades, with another severe episode occurring in 2005, said Euston Quah, a professor of environmental economics at Nanyang Technological University in Singapore.
The 1997 haze cost Indonesia, Singapore, Malaysia and southern Thailand $4.5 billion, including from health costs and a decline in tourism, Mr. Quah said. In response, Asean members developed a Regional Haze Action Plan to monitor and combat the pollution caused by land and forest fires. In 2002, they signed the Asean Agreement on Transboundary Haze Pollution.
Ten years later, Indonesia remains the only country in the bloc not to have ratified the agreement. However, at an Asean meeting in May, environment ministers said that Indonesia had begun the process of ratification, according to a statement on the body’s Web site.
Mr. Quah said he believed that the Indonesian government was not ready to meet the terms of the agreement. For example, he said, it would have to demonstrate a speedy response from all levels of government when fires broke out, a challenging task in the huge archipelago.
At the May meeting, the Asean ministers noted that Indonesia had reduced the number of hot spots, areas with the potential for uncontrolled fires, but environmental experts say that better law enforcement is needed.
While clearing land by burning is now banned in Indonesia, Mr. Quah said he was not aware of a single case in which a plantation owner had been prosecuted for a fire set on his property. He said the government should also provide incentives for villagers to report fires before they get out of control.
“If they report fires early, then they should be rewarded, either with gifts in kind or money so that we can control the small fires quickly,” Mr. Quah said.
Malaysia has provided Indonesia with firefighting equipment and firefighters, while Singapore has supplied satellite-imaging equipment to detect hot spots, he said.
Kurnia Rauf, director of the forest fire control division in the Indonesian Forestry Ministry, said that tracking down the people responsible for illegal burning was difficult. “They set fires to open the area for planting because it’s much faster and easier,” he said.
印尼林业部山火控制局的主任库尔尼娅·拉乌夫（Kurnia Rauf） 说，非法放火人员的追查工作很困难。“他们之所以要烧荒，是因为这个方法快速便捷，”他说。
He added that his division was trying to educate people about hot spot indicators. Local forestry officials were also leading ground checks, he said, and people could report hot spots to the forest fire control task force via cellphone.
Anthony Tan, executive director of the Center for Environment, Technology and Development, Malaysia, an independent research organization in Kuala Lumpur, urged a broad view of the problem. He said that while blame was typically directed at Indonesia, fires in other countries also contributed to the haze. “Asean as a bloc has to look at this problem as an Asean problem,” he said.
安东尼·陈（Anthony Tan）是马来西亚环境科技发展中心执行主任 ，该中心是吉隆坡的一个独立研究组织。他敦促大家从更为宏观的角度来看待这个问题。他说，罪责虽然通常落在印尼方面，但其他国家的火灾也对阴霾的产生负有责任。“东盟是一个整体，必须把这个问题当成整个东盟的问题来对待，”他说。