Bio CNG (Compressed Biogas) plants are advanced renewable energy systems that process organic waste, agricultural residue, or animal dung to produce clean, sustainable fuel. The process involves anaerobic digestion, where microorganisms break down organic material in the absence of oxygen, producing raw biogas a mixture of methane, carbon dioxide, and trace gases. This raw biogas is then purified to remove CO₂, hydrogen sulfide, and moisture, resulting in Bio CNG, which has over 90% methane content. The final product is compressed and stored under high pressure. In addition to fuel, Bio CNG plants also produce digestate, a nutrient rich organic fertilizer. These plants promote waste to energy solutions, reduce dependence on fossil fuels, lower greenhouse gas emissions, and contribute to circular economy models. Bio CNG plants can be installed at various scales, from small community units to large industrial setups, and are particularly valuable in rural areas, food processing industries, and municipalities with high organic waste output.