All tax deductions for December 2018 need to be deposited latest by 7th January 2019.
Filing of TDS Returns for the quarter ended December 2018 (FY:2018-19 Quarter 3) is already under way since 1st January and the last date is 31st January 2019.
Last date for filing TCS return is 15th January, 2019 and for issue of TCS certificate 30th January, 2019.