Abstract :

The Total Electron Content (TEC) depletion near the equatorial ionization anomaly crest region in the Indian ionospheric sector has been analyzed during the year March 2005 to February 2006, and May 2016 to August 2017, low solar activity periods of 23rd and 24th solar cycle respectively. TEC data from March 2005 to February 2006 is recorded by GPS Ionospheric Scintillation and TEC Monitor (GISTM) GSV4004A and data from May 2016 to August 2017 is obtained from a multi-frequency multi-constellation Global Navigation Satellite System (GNSS) receiver installed at Bhopal (23.2