Abstract Coal contains naturally occurring radionuclides arising from the uranium and thorium series and 40K. Coal burning is thus one of the sources of technologically enhanced exposures to natural radionuclides. Emissions from thermal power stations in gaseous and particulate form contain the radioisotopes, which are discharged to the environment causing radiation exposure to the population. This paper gives the results for coal and fly-ash samples from four thermal power stations in India. The radiation exposures due to the naturally occurring radionuclides discharged from these thermal power stations and those resulting from operation of nuclear power stations of Boiling Water Reactors (BWR) and Heavy Water Reactors (HWR) type are compared. From this study it is observed that exposure to the general population from ionising radiation originating from radionuclides from thermal power stations burning coal is as hazardous, if not more so, than exposure to radionuclides emitted from nuclear power stations of the type operating in India.