The Amazon rainforest has seen a record number of fires this year, according to Brazil's space research agency.
The National Institute for Space Research (Inpe) released data on Tuesday claiming that there has been an 83 per cent increase from the same period in 2018.
The head of the agency, Ricardo Galvão, was sacked by Jair Bolsonaro, the Brazilian president, earlier this month over disputes about its deforestation data.
Mr Bolsonaro had accused Mr Galvão of trying to undermine the government by "lying" about the scale of deforestation in the Amazon. It followed an Inpe report that showed an 88% increase in June compared to the same month a year previously.
Smoke from the infernos caused an hour-long daytime blackout in Sao Paulo on Monday as smoke blew over 2,700km from the states of Amazonas and Rondonia.
Inpe claimed to have logged 72,000 fires between January and August - the highest number since records began in 2013. It said it had detected 9,500 fires since Thursday, the majority of which are in the Amazon region. There were some 40,000 fires in the whole of 2018.
Previously, the worst recent year was 2016, which saw over 68,000 fires.
Satellite images showed the northern state of Roraima covered in smoke, and neighbouring Amazonas has declared a state of emergency. Wildfires are common in Brazil's dry season which last from three to five months yearly, the timing of which varies according to location. Sometimes they are deliberately caused in illegal attempts to remove trees to clear space for cattle ranches.
Conservationists have blamed Mr Bolsonaro for the fires, saying he has encouraged loggers and farmers to clear the land.
Scientists say that losses have increased since he assumed office in January, and surging deforestation in Brazil has seen him nicknamed “Captain Chainsaw”.
Previous governments had reduced deforestation through action by federal agencies and fines, but convictions and confiscations of timber have fallen this year.
However, Nasa, the US space agency, says there has been a reduction in the amount of fires in the Amazon basin as a whole.
While it says there has been an increase in Amazonas and Rondonia, it claims a decrease in the regions of Mato Grosso and Pará.
Inpe researcher Alberto Setzer told Reuters: "The dry season creates the favourable conditions for the use and spread of fire, but starting a fire is the work of humans, either deliberately or by accident."
Photographs of the blazes have gone viral on social media, sparking calls for an end to deforestation.