New Delhi: Prime Minister Narendra Modi on Wednesday paid tribute to former President A.P.J. Abdul Kalam on his first death anniversary, saying that his death has created an "irreplaceable" void. "It's been a year since our beloved Dr. A.P.J. Abdul Kalam left us and created a void that is irreplaceable. My tributes to this great personality," tweeted Modi. While delivering a lecture at the Indian Institute of Management (IIM), Shillong, Kalam collapsed and died due to cardiac arrest on this day last year.