Chandrababu Naidu/ File pic

Andhra Pradesh Chief Minister N Chandrababu Naidu on Tuesday vowed to make Amaravati a world-class greenfield city, with the happiness of people as its basic foundation. "It is a unique opportunity for us to build a greenfield city, the capital of the state. It will be a blue and green city that will be the most liveable and will emerge as one of the top five best cities in the world," he said while inaugurating the three-day 'Happy Cities Summit' here this afternoon.