The Central Board of Indirect Taxes and Customs Vide Notification No 61/2018 – Central Tax dated 5th November 2018 has notified seeks to exempt a supply from one PSU to another from the provisions of TDS under GST.
http://www.cbic.gov.in/resources//htdocscbec/gst/notfctn-61-central-tax-english2018.pdf;jsessionid=F7CDBFE56BBEEE1F69C5 F3BEC0999AF4