COLOMBO - Sri Lanka suffered its worst nationwide power cut in 20 years Sunday causing water shortages and transport and trade disruptions across the country, officials said. The national grid switched off early afternoon and attempts to reconnect failed as the system was unable to cope with night time demand, a spokesman for the state-run Ceylon Electricity Board (CEB) utility said. However, after about seven hours several areas of the capital received electricity while the authorities announced a step-by-step restoration of power throughout the island.