New Delhi: The President, the Vice President and the Lok Sabha Speaker have greeted the people on Holi and hoped that the festival of colours will strengthen the spirit of unity and harmony among the people. The President Mrs Pratibha Devisingh Patil said the unique festival of colours should may bring joy and happiness and foster the spirit of unity and harmony among the citizens. Vice President Hamid Ansari, in his message, said Holi is celebrated with joyous gaiety and the festival reinforces the spirit of unity in diversity.