The primary market deals with the issuance of securities. RBI acts as a banking and debt manager to the central and state governments.
The RBI issues government debt based on 1. Market liquidity conditions 2. The maturity of the existing issues and desired maturity 3. Yields in the primary and secondary market 4. Fiscal Deficit.
RBI releases an Issuance Calendar to help investors plan to invest in government securities.
Here is a sample: http://pib.nic.in/newsite/PrintRelease.aspx?relid=188040
The issuance by RBI may be a reissue of existing securities or issue of new securities. The issuance is carried through auction. In the case of reissuance, as the coupon and maturity are already known, the market participants are required to bid on the price. On the other hand, in case of new issue RBI announces the tenor and amount and the investors are required to bid on the security by quoting the desired yield.
RBI auctions securities in both by Uniform Price Method at which all participants are allotted securities at the same price which is the highest at which issuer can get the whole issue subscribed or Multiple Price Method at which securities are allocated at different prices and yields quoted by the investors.
SECONDARY MARKET - CLEARING CORPORATION OF INDIA (CCIL)
CCIL has created Negotiated Dealing System (NDS) which is an electronic platform for trading of government securities. CCIL also developed the NDS-Call platform which is used for trading in call money and NDS-Auction which is used for Treasury Bills auction for RBI.
Once RBI issues government securities, they are available for trading on the NDS Order Matching System (NDS-OM). In the secondary market for the government securities, CCIL acts as a counterparty to both buyers and sellers and guarantees settlement.
Related Links https://www.ccilindia.com/Pages/default.aspx