https://www.indiatoday.in/technology/news/story...
BSNL has been allotted fresh Pan India liberalised spectrum and an additional block of 5 MHz in the 2100 MHz band in 20 telecom circles by the Department of Telecommunications (DoT).
earlier 5mhz in 2100mhz was used for 3g and and at few places they are using for 4g instead of 3g. with this extra 5mhz they can have both 3g and 4g or more bandwidth for 4g.