India and Germany’s new defence road map could give New Delhi fresh momentum in its long-running push to modernise its undersea fleet, while helping Europe expand its security role in the Indo-Pacific, experts say.

The two countries signed a Defence Industrial Cooperation Road Map in Berlin on Wednesday, with Indian Defence Minister Rajnath Singh and his German counterpart, Boris Pistorius, agreeing to deepen collaboration in development, production and niche technologies.

The agreement was...