Surat Lignite Power Plant - 4X125 MW, Unit # I to IV: Biennial Maintenance Contract for Monitoring & Maintenance services for STP and Recycling Plant at colony & Monitoring services for PT , ETP & Run Off Pond System at DM Plant in Plant premises and Environmental Monitoring & Ambient air Monitoring in Plant, Valia & Mangrol Lignite Mines & Vastan Lignite Mine (Including Lime stone Pit) for two years of contract period.