Assembly polls in Tamil Nadu and Kerala are expected to be held in April-May. With elections coming closer, BJP is toiling in its "mission south". On Sunday, Prime Minister Narendra Modi is scheduled to inaugurate the Chennai Metro Rail Phase-I extension, completed at a cost of Rs 3,770 crore, and commission passenger services from Washermenpet to Wimco Nagar.Modi will inaugurate the electrification of a single-line section of 228 km, completed at a cost of Rs 423 crore. This will enable free flow of traffic without the need for a change of traction between Chennai Egmore and Kanyakumari and would result in saving of Rs 14.61 lakh per day on fuel cost, it added.