Announcing the decision tonight, India said that "one country" has created an environment that is not conducive to the successful holding of the Summit.
"India has conveyed to current SAARC Chair Nepal that increasing cross-border terrorist attacks in the region and growing interference in the internal affairs of Member States by one country have created an environment that is not conducive to the successful holding of the 19th SAARC Summit in Islamabad in November 2016," External Affairs Ministry said in a statement.
"We also understand that some other SAARC Member States have also conveyed their reservation about attending the Islamabad Summit in November 2016," it said.
According to sources, Afghanistan, Bangladesh and Bhutan are the other countries which have said no to attending the Summit.
In its communication to Nepal, India has said it remains steadfast in its commitment to regional cooperation, connectivity and contacts but believes that these can only go forward in an atmosphere free of terror.