In Maharashtra, polling has begun in 10 municipal corporations of the state, including Mumbai. Elections are being held for Thane, Ulhasnagar, Pune, Pimpri-Chinchwad, Solapur, Nashik, Akola, Amravati and Nagpur municipal corporations.The 10 civic bodies have an electorate of over 2 crore and will elect 1,244 candidates. In the 227-seat Mumbai Corporation, the election is a fiercely fought affair. A triangular contest is on cards between the Congress-NCP combine, Shiv Sena-BJP-RPI alliance and the Raj Thackeray-led MNS. It is a challenge for the Congress-NCP combine that aims to dethrone the Sena-BJP combine, at the helm of civic affairs for the last 16 years.Meanwhile, police and security forces are all geared up to ensure an incident-free balloting. Mumbai Police Commissioner Arup Patnaik said over 20,000 policemen have been deployed in Mumbai city alone.