The Global Fund to Fight AIDS, Tuberculosis and Malaria is the world's leading source of international financing to support malaria control programs in the world.
As world gold prices have surged, small-scale "artisanal" gold mining has become the world's leading source of mercury pollution.
It is the world's leading source of both water pollution and deforestation.
A bumper harvest last year established Afghanistan as the world's leading source of opium, the United Nations estimates.
Barring an unexpected turn of events, Afghanistan can be expected to regain its status as the world's leading source of heroin in a year or two.
China is regarded as the world's leading source of illegally copied movies, software and other goods, despite repeated government promises to stamp out the underground industry.
The United States recently announced that it was providing $780 million to combat illicit drugs in Afghanistan, the world's leading source of opium, over the next year.
Pro Piano, which calls itself "the world's leading source for Hamburg Steinways," went into the record business a few years ago and is now presenting concerts as well.
Pro Piano, which calls itself "the world's leading source for Hamburg Steinways," went into the record business a few years ago and is presenting concerts as well.
Only a few years ago, many studies projected that China would emerge as the world's leading source of carbon dioxide by 2020, but these recent developments appear to have put off that day by years or even decades.
Now used by millions of drivers, it has grown to become the world's leading source of parking information covering more than 20m car park spaces in 25 countries.
