A fire broke out at Notun Bazar slum in Kalyanpur in the capital tonight. The fire broke out at the slum around 10:03pm, said Mahfuz Riben, duty officer of the Fire Service and Civil Defence headquarters control room. Nine units of fire-fighters rushed to the spot and are working to douse the blaze, said Mahfuz Riben. The reason behind the fire could not as yet be ascertained.