Certainly! Here’s a general comprehension of the T-90 “Bhishma” Tanks Used by India:
T-90 Bhishma: Guardian(s) of India
Bhishma Mk.I:
The Bhishma Mk.I is the first rendition of the Bhishma series built indigenously in India, being first built in 2001. Essentially just a License-Built T-90S, although built with some indigenous parts, and seeing the use of the French Catherine-FC thermal sight. Unlike typical Russian T-90As, Indian Bhishma tanks do not include the well-known Shtora-1 passive electronic countermeasure system, as it was considered obsolete by the Indian military, rather having them replaced with additional Kontakt-5 ERA blocks.
Bhishma Mk.II:
(NOTE: Infornation Regarding the Bhishma Mk.II is sparce, so some information may be vague or ommited.)
The Bhishma Mk.II is a relatively-minor upgrade to the Bhishma series, mainly only seeing the further indigenization of parts used in the tanks and minor improvements to the tank in general, first being built in the early 2010’s.
Bhishma Mk.III:
(NOTE: Infornation Regarding the Bhishma Mk.III is also sparce, so some information may be vague or ommited.)
The Bhishma Mk.III is the latest version of the Bhishma to date, first being announced in May 2024, The Bhishma Mk.III sees significant upgrades, seeing a majority of its parts such as its thermals, engine, and LRF being designed and built in India, and now includes technologies and equipment found on India’s Arjun MBT’s such as its FCS, and is reportedly capable of firing the SAMHO ATGM and Mk.II APFSDS. Further technologies such as a APS, loitering munitions, and other upgrades are also planned for later production blocks.
Bhishma SK:
The Bhishma SK is simply a license-built T-90SK, being a Commander’s T-90, having upgrades to its radio and navigation systems, however still is near-identical to standard Bhishma tanks.
Bhishma TWMP:
The Bhishma TWMP is already found in WarThunder as a squadron vehicle for the British Tech Tree, Being a Bhishma Mk.I with the Indigenous TWMP (Track-Width Mine Plow).
Bhishma Biathlon Variant (2015):
The Bhishma Biathlon Variant is a Mk.II Bhishma Tank that sees the removal of components such as a its frontal ERA blocks, side skirts, and some internal components, with upgrades to its engine and FCS to compete in the annual Russian Tank Biathlon. As a result, the tank is significantly faster and more nimble than its frontline counterparts, at the loss of significant protection.
Bhishma II:
The Bhishma II is to be locally-produced T-90MS for the Indian military, seeing a majority of its parts to be indigenously designed and built. Funding and a procurement of licenses have been ongoing for the last decade, however have largely been put on hold due to the current Russian war in Ukraine.
T-90MS:
The T-90MS is the Russian export-variant of the T-90AM, largely meant for purchase by India, as a result being specialized to better function in environments found in India.
I hope this all helps! If you have further questions or I mentioned something incorrect, please let me know! And if you want similar explanations about other vehicles/series, such as the Ajeya or Arjun, do say!