<br/>Government says it is vigilant against all forms of challenges posed by terrorism and has taken a series of measures to strengthen the security apparatus. Addressing the joint budget session at the jampacked historic Central Hall of Parliament, the President Mrs Pratibha Devisingh Patil said though the infiltration level in Jammu and Kashmir across the Line of Control has gone up, the security situation has improved significantly in the border states. Mrs. Patil said, the security scene has also improved substantially in the North-East but the Left wing extremism continues to be a great cause of concern. Mrs Patil asserted that zero tolerance of terrorist’s activities is the government’s principled policy. Highlighting the details of the steps taken by the government following Mumbai terror attacks in November 2008, she said a multi agency centre is functioning round the clock in the Intelligence Bureau to coordinate intelligence inputs. The President said, coastal security has also been strengthened.