Why is May 11 observed as National Technology Day?

India observes National Technology Day on May 11 to mark the success of Operation Shakti, the 1998 nuclear tests conducted at Pokhran in Rajasthan. Former Prime Minister Atal Bihari Vajpayee declared the day in 1999 to celebrate India's scientific and technological achievements. The same day also saw successful tests of the indigenous Hansa-3 aircraft and Trishul missile.