The 'Decade Challenge' is a social media trend where individuals recreate fashion and beauty looks from past decades, such as the 1960s, 1990s, and early 2000s, using modern products. Participants aim to capture the essence of a chosen era through makeup, hair, and outfits, adapting styles to suit contemporary preferences and Indian conditions like skin tones and climate. The trend involves comparing old and new looks, often sharing side-by-side photos online, with an emphasis on using accessible, budget-friendly products.