The 2023 Sri Lankan blackouts were a series of nationwide electrical blackouts which occurred in Sri Lanka on 9 December 2023. Blackouts began at around 5.00 pm SLST (UTC+5:30) and lasted for over three hours. The nationwide blackouts occurred due to a systematic failure in the main supply chain and due to a breakdown of the Kotmale Biyagama transmission line.[1][2][3]