By Tony Smith and Angus Crawford.
The news is from the BBC.
The caption is media.
A trader told the BBC that he can get at least 100 canisters of highly polluting HFCs.
A black market in greenhouse gases has been uncovered by a BBC investigation.
A trader suggested that hydrofluorocarbons could be smuggled on coaches, after the BBC found that they were advertised and sold illegally via social media.
HFCs are used in many places.
The EU and UK want to phase them out in favor of cleaner alternatives.
The black market for HFCs has grown because older machinery still runs on them.
UK law states that only registered companies can import, sell or use HFCs, and buyers must have an F-Gas certificate.
The investigation began at the Romania-Ukraine border, where HFCs made in China have been smuggled through in the boots of cars.
We found scores of online adverts posted by local traders offering the gases for sale and met one trader, called "George", who said he could get large quantities of HFCs.
He opened the boot of his car to reveal two canisters of HFCs after directing us to a quiet country road near the border crossing.
They were offered for around £100 each. They sell on the UK's illegal market.
The caption is media.
A trader in North London is selling HFCs.
To get the gases into the UK, he suggested that they be smuggled into the luggage compartment of passenger coaches that leave from the local bus station.
He said he used to send 70 or 80 at a time to Germany using this method, but it was just a question of finding the right driver and paying them.
The image caption is.
The bottles the BBC bought were emptied by a legitimate supplier and the gases were safe.
HCFs were developed as an alternative to ozone-depleting chemicals, which were banned under the Montreal Protocol.
The deal banned the use of chlorofluorocarbons.
HFCs are odourless and man-made.
They are used in air conditioning, industrial chillers, and fridges and can be found in some aerosol propellants and fire protection fluids.
Some HFC blends are thousands of times more potent than carbon dioxide.
The UK wants to reduce the use of HFCs by 69%.
The image caption is.
The Environmental Investigation Agency warned of the impact HFCs had on global warming.
The illegal HFCs trade is one that most people don't know about, but the huge profits on offer made it attractive to criminals, said a senior campaigner for the Environmental Investigation Agency.
Bottles made in China for less than $30 can be found in the UK for more than $200.
Ms Walravens said that HFCs had a huge impact on global warming.
The executive director of 2Celsius called for the authorities to work together to stop the trade.
We need to do as much as we can as quickly as possible, I think this should have happened yesterday.
The illegal HFC bottles are distributed across the EU and into the UK.
They were advertised for sale on the Facebook marketplace.
One seller in North London was contacted. Since 2006 disposable canisters have been banned for sale because he was not registered to handle gases.
According to a report by the EIA, the illegal HFCs trade made up between 20% and 30% of the European market.
The illegal HFCs trade is sometimes viewed as a victimless crime because it looks like nobody gets hurt.
He said that the profits from this will go back into organised crime, where they will be used for much darker activities.
More global warming can happen because the regulation hasn't been upheld.
The UK's Environment Agency is committed to ensuring that businesses comply with regulations to reduce emissions from HFCs, and will take strict enforcement action where necessary.
The company was fined more than a million dollars for breaching F-gas regulations.
It was the second time that the company had been fined by theEA.
Climate change.
The Environment Agency.
