Reduction of uncertainty of Primary Time Scale generating UTC(NPLI) to 2.8 ns

CSIR-National Physical Laboratory (CSIR-NPL), New Delhi is the custodian of primary time scale generating Indian Standard Time (IST). In the present paper we report the major reduction of the uncertainty of Primary Time Scale from 20 ns to 7.2 ns and finally to 2.8 ns. We also discuss current time dissemination methods being employed and the tasks undertaken for upgradation and strengthening of the primary time scale to serve the pan India in a better way at par with the international level.