Central Pollution Control Board Issues New Classification Directive for CBG/Bio-CNG Plants

The Central Pollution Control Board (CPCB) has issued a directive under Section 18(1)(b) of the Water (Prevention & Control of Pollution) Act, 1974, and the Air (Prevention & Control of Pollution) Act, 1981. The directive, titled "Directions under section 18(1)(b) regarding harmonization of classification of industrial sectors under Red, Orange, Green, White, and Blue categories," instructs all State Pollution Control Boards (SPCBs) and Pollution Control Committees (PCCs) to adopt the revised classification of Compressed Biogas (CBG/Bio-CNG) plants into Red, Blue, and White categories based on their Pollution Index scores. This directive, CP-18/1/2023-IPC-VI-HO-CPCB-HO/855, was issued on March 25, 2025, as part of the Classification-2025 framework to enhance environmental management.

Overview of the Directive

The document outlines a legal and technical framework for classifying CBG/Bio-CNG plants based on pollution control regulations.

Roles of the CPCB:

1. Regulatory Authority – The CPCB coordinates activities of SPCBs and PCCs to ensure compliance with environmental standards.

2. Technical Guidance – The CPCB provides support and guidance to SPCBs and PCCs in implementing pollution control measures.

Classification-2025 Methodology

1. categorization of 419 industrial sectors into five categories: Red, Orange, Green, White, and Blue.

2. Index (Plindex) methodology assigns equal weightage to water, air, and hazardous waste scores.

3. Introduction of the Blue Category to recognize essential environmental services managing pollution from domestic and household activities.

Revised Classification of CBG/Bio-CNG Plants

1. Previous Classification: Initially classified under Red, Orange, and White categories.

2. Review Process: Conducted in response to industry requests, analyzing the impact of feedstock types, including:

•  Municipal Solid Waste (MSW)

• Agro-residue

• Energy crops

• Industrial waste

3. Reclassification Rationale:

• Plants using certain feedstocks with high littering potential were deemed suitable for the Blue Category.

CBG/Bio-CNG plants are now classified into five sub-sectors under Red, Blue, and White categories, based on Pollution Index scores.

Directive to SPCBs and PCCs

Under the Water and Air Pollution Acts, CPCB has mandated all SPCBs and PCCs to implement the new classification system as specified in Annexure-I of the directive.

This directive marks a significant step toward harmonizing industrial sector classification and ensuring a balanced environmental approach in regulating CBG/Bio-CNG plants.