Group 1 - The article discusses tax incentives for enterprises engaged in biogas comprehensive development and utilization projects, specifically highlighting the "three exemptions and three reductions" policy for corporate income tax [2][3]. - Taxpayers involved in biogas projects related to livestock and poultry breeding will be exempt from corporate income tax for the first three years and will have a 50% reduction for the next three years after the first revenue is generated [2][3]. Group 2 - Conditions for enjoying the tax benefits include having a single biogas unit with a minimum volume of 300 cubic meters and an average daily biogas production of at least 300 cubic meters, complying with national technical standards [3]. - Projects must ensure that wastewater discharge, waste residue disposal, and biogas utilization meet national and local standards to avoid secondary pollution [3]. - The project must include complete facilities for raw material pretreatment, comprehensive utilization or further processing of biogas residues and liquids, and systems for biogas purification, storage, distribution, and utilization [3].