Firefighters have been battling wildfires spreading through a national park in Brazil and choking the capital, Brasilia, in smoke.

More than 490 firefighters on Monday were trying to extinguish blazes that have already burned through 2,000 hectares (4,942 acres) of the Brasilia National Park conservation area. It’s just the latest of many wildfires in the country, which is experiencing a historic drought.

There are four main fire fronts, all concentrated in the eastern region of the park, according to a statement from ICMBio, the government agency that manages the park.

Three aircraft are using water to tackle the flames, and a helicopter is helping to monitor the burned areas, the ICMBio statement said.

The fire “spread very quickly because of wind speed, low humidity, and it is very hot,” said Joao Paulo Morita, an ICMBio fire management coordinator.

Federal police are investigating the case, as the fire was started by human activity, the statement said.

The fire has smothered Brasilia, with columns of black smoke visible from several points in the city.

The country has been enveloped in smoke in recent weeks, as fires have raged in the Amazon rainforest, the Cerrado savanna and the Pantanal wetlands.

These uncontrolled, human-made fires have ravaged protected areas and spread smoke over a vast expanse, causing air quality to plummet.

A Supreme Court justice issued a ruling on Sunday authorising the government to direct extra funds towards combatting forest fires and hiring firefighters.

The country is enduring its worst drought since nationwide measurements began more than 70 years ago, with 59 percent of the country affected. Major Amazon basin rivers are registering historic lows.

Scientists say that climate change makes extreme weather more likely, favouring conditions for events such as wildfires and floods.