The Environment Protection Act, 1986 indeed empowers the Government of India to lay down standards for emission or discharge of environmental pollutants from various sources, which is critical for maintaining environmental quality and public health. However, while public participation is encouraged in environmental governance, the Act does not explicitly stipulate the requirement for it in the same structured manner as setting pollutant standards. Therefore, the correct option is "2 only," as the Act primarily focuses on regulatory frameworks and standards rather than detailing public participation procedures. This understanding aligns with UPSC-level discussions on environmental legislation and governance, which emphasize regulatory frameworks over procedural specifics.