This book blends mathematical concepts with environmental awareness using real-world data from the Yamuna River. Its purpose is to make mathematics practical, purposeful, and relevant for students, educators, and innovators. Highlights: • Real Math, Real Context—Explains Yamuna's pollution crisis through equations. • All Branches of Math—Algebra, Geometry, Trigonometry, Statistics, Calculus applied to real issues. • Fact-Based—Supported by CPCB reports, NCERT data, journals, and news. • Innovative Models—Oxygen decline, algae growth, sewage costs, pollution spread. • Future-Ready—Aligned with NEP 2020, project-based learning.