The star of Indian defence is called S-400. In October 2018, India signed a $5.13 billion deal with Russia to procure 5 squadrons of the S-400 Triumf air defence system.
The S-400 known in India as "SUDARSHAN CHAKRA" is designed to counter threats from across the world. It can engage aircrafts, drones. cruise missiles, and ballistic missiles at ranges upto 400km and altitude upto 30km.
The US opposed the deal warning it could trigger sanctions under CAATSA(Countering America's Adversaries Through Sanctions Act). Concerns were raised that deploying the S-400 alongside American systems could compromise US military technology, especially under the CAATSA provisions.
India stood firm on its decision emphasizing national security and strategic autonomy despite US warnings that the deal could invoke CAATSA. Nonetheless, deliveries began in 2021, highlighting India's commitment to an independent defense policy amid global pressure :)