TRAI’s recommendation on spectrum dated 27th Jan 2016 recommends the following block sizes for respective bidders based on their status (Page 30, Table 2.13).
In short a licensee already having spectrum in 800, 900 and 1800 MHz band can bid at a much lower granularity of block size compared to a new bidder (without any spectrum in that band). This condition is similar to the condition that we had in the last auction which had resulted in some unsold spectrum, and abnormal increase in bid prices. Read my earlier note “Mystery of unsold spectrum”.