India can now mass produce the intermediate range ballistic missile (IRBM) - Agni- and has embarked on Phase-2 of the project aimed at substantially increasing its range and impact, the Scientific Adviser to the Defence Ministry, Dr. A.P.J. Kalam, announced here on Sunday. The Centre has given its approval to the project to develop a new version of the Agni, which would be modular in construction, giving it the flexibility to use different combination of fuels, Dr. Kalam told newspersons.