Complex sentence: The Dassault Mirage 2000, known as "Vajra" (Sanskrit for Thunderbolt) in Indian service, is the primary multirole fighter, the IAF currently operates 51 Mirage 2000Hs which are currently being upgraded to the Mirage 2000-5 MK2 standard.
Split into simpler sentences: The Dassault Mirage 2000, known as "Vajra" (Sanskrit for Thunderbolt) in Indian service, is the IAF's primary multirole fighter. The IAF currently operates 51 Mirage 2000Hs which are currently being upgraded to the Mirage 2000-5 MK2 standard.