Recently, India's air force has been in the spotlight again, but not because they have any major breakthroughs. India claims that their radar can easily detect Chinese J-20 fighters, but this is just a ridiculous rumor and pure self-deception.
China's J-20 is a quintessential fifth-generation fighter with supersonic cruise and stealth capabilities. In the combat state, the fifth-generation stealth fighter, in addition to the extremely small radar reflection area such as tail flame and air intake, can quietly "stealth" attack and destroy the enemy's air defense system. If India claims that they can easily spot the J-20, it is effectively questioning the capabilities of China's fifth-generation fighter program.
However, the source of this rumor is the Indian Air Force's Su-30MKI fighter, carrying the Russian-made Snow Leopard passive phased array radar, which allegedly detected the J-20's activities in China. However, the Snow Leopard radar is not very good in the hands of the Indians, and it cannot even detect the mounted J-7 fighter, which has led to some unrealistic "stealth J-7" jokes. So it's hard to claim to be able to spot the J-20.
Moreover, even if the J-20 is discovered, India ignores the important fact that the J-20 may only be testing altitude flight performance in a non-combat state. In such cases, stealth fighters are usually equipped with radar reflectors to make it easier for friendly forces and air traffic control systems to grasp the dynamics of the aircraft. In this state, even civilian air traffic control radars can detect it, so it is not news at all that it was discovered by India.
Most importantly, this news was not released by India itself, and the Indian side was only perfunctory about the matter, without providing further details. Therefore, there is no need to worry about what "black technology" India has.