As India and Pakistan look to build upon the recent ceasefire agreement, PM Narendra Modi Tuesday wrote to his counterpart Imran Khan and extended greetings to the neighbouring country on the occasion of Pakistan National Day and underlined that an environment free of terror was imperative for improvement in ties.As India and Pakistan look to build upon the recent ceasefire agreement, PM Narendra Modi Tuesday wrote to his counterpart Imran Khan and extended greetings to the neighbouring country on the occasion of Pakistan National Day and underlined that an environment free of terror was imperative for improvement in ties.