Poppy cultivation and production in Afghanistan has decreased sharply, according to a United Nations report, BBC reported.
The UN Office on Drugs and Crime says opium cultivation has dropped by 22% in a year and production by 10%, with the biggest fall in Helmand province.
But the figures are still higher than three years ago, when British troops began fighting Taliban militants there.
The report came ahead of a meeting in Paris of European and US officials to discuss a new strategy in Afghanistan.
Meanwhile, vote counting is still ongoing from last month's Afghan election, which has been mired in claims of mass rigging.
The security situation in the country has been deteriorating, and the death toll of foreign troops is at a record high.
The UN says the drugs trade, which helps fund the insurgency, threatens the legitimacy of the Afghan state.
The UNODC report called on the international community to sustain progress in Afghanistan, which produces 90% of the world's heroin.
It praised the introduction of UK-backed "food zones", which distribute wheat seed for farmers to plant.
'Enormous cost'
The report said 20 of the country's provinces were now poppy-free, but the BBC's Chris Morris in Kabul says that does not mean they are free of the refining and trafficking of drugs.
The UN report said that the price of opium was at a 10-year low.
The UNODC's Executive Director, Antonio Costa, said: "The bottom is starting to fall out of the Afghan opium market. These results are a welcome piece of good news and demonstrate that progress is possible."
But he warned that Afghan drugs still have catastrophic consequences: funding criminals, insurgents and terrorists, encouraging corruption and undermining public trust.
This year there were 69,833 hectares devoted to poppy growing in Helmand, a sharp fall from 103,590 hectares in 2008, the report found.
However, this year's figure was also more than double the 26,500 hectares used for poppy growing in the province in 2005, the year before British troops deployed in the area.
Helmand continues to account for nearly 60% of the country's total production of the drug, the UNODC report said.
Political instability
Ahead of Wednesday's meeting in Paris by European and American officials to discuss Afghanistan, US envoy Richard Holbrooke told French media that a summer offensive in the south to flush out the Taliban had yielded results.
"The coalition forces including the British and Americans have done vast damage to the Taliban, disrupted them, captured major caches of opium, heroin and drug paraphernalia," Mr Holbrooke told France 24 television.
Afghanistan faces mounting political instability over last month's presidential election, which has been marred by delays in vote counting and allegations of fraud.
Vote tallies released on Monday from the 20 August poll showed President Hamid Karzai leading with nearly 46%, and his nearest rival, Abdullah Abdullah, at 33.2%. Mr Karzai needs 50% of the votes to avoid a run-off.
Foreign troops fighting in Afghanistan endured their deadliest month yet in August when 77 soldiers died, according to an independent website - icasualties.org - which tracks military casualties.
More than 300 troops have died in Afghanistan so far this year, making it the deadliest year since the 2001 US-led invasion to overthrow the Taliban.
Some 30,000 extra US troops have been sent to Afghanistan since President Barack Obama ordered reinforcements in May, almost doubling his country's contingent and boosting the Western total to about 100,000.