The new policy was approved by the Union Cabinet chaired by Prime Minister Narendra Modi.
The metro policy will talk about standardising norms and developing a procurement mechanism for implementation of the projects. It will also talk about funding and financing, officials said.
At present, metro projects with a total length of more than 350 km are operational in eight cities -- Delhi, Bengaluru, Kolkata, Chennai, Kochi, Mumbai, Jaipur and Gurugram.
Metro projects are also under way in Hyderabad, Nagpur, Ahmedabad, Pune and Lucknow.