The lush-green mountains in the background usually make the famous Nainital lake in Uttarakhand state of northern India more picturesque. But for several weeks now haze from forest fires has hidden the mountains, and the lake's beauty has visibly shrunk. "You can smell the haze from this side of the lake where I live," said Shekhar Pathak, an expert on the history of forests in the region. "Not just the pine trees that are highly prone to fires, even the oak forests are burning and that means the situation is quite serious." Locals in areas worst-affected by forest fires told the BBC they don't sleep at night these days. "We wake up in the middle of the night and check around the forests to make sure the fires are not approaching us," said Kedar Avani of Banaa village in Pithoragarh district, the eastern-most Himalayan district in the state. "Fires have eaten up our haystacks and grass stored for our livestock, and now we fear our houses will be gutted too." Mr Avani said that the fires were so strong that the heat could be felt even at a distance of 20 metres. "There is no way we can put them out," he said. Record forest fires Scientists say the forest fires in some parts of northern India and neighbouring Nepal have been the strongest in the past 15 years. The European Union's Copernicus Atmospheric Monitoring Service (CAMS) said that Uttarakhand's forest fires emitted nearly 0.2 mega tonnes of carbon in the past one month, a record since 2003. Based on the analysis of satellite pictures, it estimated Nepal emitted nearly 18 mega tonnes of carbon in the same period, the highest since 2016 when it emitted 27 mega tonnes of carbon. "This shows the intensity with which the fires are burning in the region and it is quite worrying," said Mark Parrington, senior scientist at CAMS. Nearly 20 people have been reportedly killed by the fires in Uttarakhand and Nepal. Hundreds of thousands of hectares of forests are believed to have been razed although official figures are yet to be published.