National Renewable Energy Day is observed worldwide every March 21 to promote renewable energy sources and encourage sustainable living by transitioning from fossil fuels to alternatives. Established in 2004, the day highlights the need to reduce reliance on fossil fuels, which accounted for 84% of primary energy consumption and 64% of global electricity as of 2019. The celebration emphasizes the advantages of renewable resources, such as biomass, geothermal heat, sunlight, wind, and water, which can be replenished naturally on a human timescale. Participants are encouraged to educate themselves and others about renewable energy, consider incorporating it into their lives, and share information on social media using hashtags like #NationalRenewableEnergyDay. The event also addresses the challenges posed by the fossil fuel lobby that hinders the transition to renewable energy.