A marina is a sheltered harbour where boats & yachts are kept in the water and where services geared to the needs of recreational boating are found. This is one of the explanations seen for the word Marina in WIKIPEDIA.
But the Marina in Chennai is the beach, on the Bay of Bengal and got its facelift sometime in 1880’s by Governor Elphinstone. After a few other ertswhile governments arranging for its beautification, now the current incumbent Govt. is also from its part is engaged in the beautification of the Marina Beach.
The above is one such displays announcing the same, in Tamil, for the area near the Labour Statue.