A low-pressure gas discharge lamp provided with a gas discharge vessel containing a mercury-free gas filling with an indium compound in an amount of about 1 to 10 microgram per cubic centimeter and a partial pressure in the range from 1.0 to 30 micro bar, and a buffer gas for emitting radiation in a continuous spectrum in the visible and near UVA regions of the electromagnetic spectrum, which low-pressure gas discharge lamp is also provided with electrodes and a ballast for controlling the ignition and operation of the lamp.