S-400

In October 2018, India signed a $5.43 billion deal with Russia to purchase five S-400 Triumf air defense systems. The deal was seen as a significant development in the India-Russia relationship, given the strategic importance of the S-400 system and its potential implications for India's relations with the United States. The S-400 Triumf is a surface-to-air missile system developed by Russia's Almaz Central Design Bureau. The system is designed to detect, track, and destroy a wide range of aerial targets, including aircraft, missiles, and drones, at a range of up to 400 km. It is considered one of the most advanced air defense systems in the world, with advanced radar systems and sophisticated missile technology. The purchase of the S-400 system is seen as a major boost to India's air defense capabilities, given the system's advanced technology and long-range capabilities. India has been seeking to modernize its defense infrastructure in recent years, in response to the growing security challenges in the region.

The S-400 system is expected to significantly enhance India's air defense capabilities, particularly in the context of the ongoing tensions with Pakistan and China. The system will also help India to reduce its dependence on foreign suppliers for defense equipment, given the advanced technology and capabilities of the S-400 system. The purchase of the S-400 system has raised concerns in the United States, given its potential implications for India's relations with the US. The US has imposed sanctions on Russia for its alleged interference in the 2016 US presidential election and other actions, and it has warned countries against purchasing Russian defense equipment.

The US has warned India that the purchase of the S-400 system could result in sanctions under the Countering America's Adversaries Through Sanctions Act (CAATSA), which was passed by the US Congress in 2017. The act imposes sanctions on countries that purchase defense equipment from Russia, Iran, or North Korea.

However, India has maintained that its purchase of the S-400 system is in its national interest, and it has sought to downplay the potential implications for its relations with the US. Indian officials have pointed out that the US has also imposed sanctions on several other countries for their defense purchases, and that India's relationship with Russia is based on its strategic and defense needs. The S-400 deal between India and Russia is a significant development in the India-Russia relationship and has implications for India's defense capabilities and its relations with the US. While the deal has raised concerns in the US, India has maintained that its purchase of the S-400 system is in its national interest, and it has sought to balance its relationship with Russia and the US. The S-400 system is expected to significantly enhance India's air defense capabilities, and it is likely to remain a key element of India's defense infrastructure in the years to come.