With China, Russia and the US actively building aerodynamically manoeuverable hypersonic weapons that fly over five times the speed of sound (Mach 5), defence minister Rajnath Singh has directed DRDO to move fast towards developing such arsenal to 'maintain' India’s minimum credible deterrence against adversaries.With China, Russia and the US actively building aerodynamically manoeuverable hypersonic weapons that fly over five times the speed of sound (Mach 5), defence minister Rajnath Singh has directed DRDO to move fast towards developing such arsenal to 'maintain' India’s minimum credible deterrence against adversaries.