Autoclaved AAC Blocks Classified as Cement Concrete Building Products Under GST

The Gujarat Authority for Advance Ruling (GAAR) on 8 May 2026 clarified the classification and GST rate applicable on Autoclaved Aerated Concrete (AAC) Blocks, holding that the product falls under HSN 6810 11 10 as “building blocks and bricks of cement, concrete or artificial stone.” In the case of M/s Eco Green AAC Products Pvt. Ltd., the Authority ruled that AAC Blocks are taxable at 12% GST and cannot be classified as ceramic products under Chapter 69. The Tribunal pointed out that

“AAC Blocks are manufactured through an autoclave curing process and not by kiln firing, which is a fundamental requirement for classification under Chapter 69 relating to ceramic products.”

Eco Green AAC Products Pvt. Ltd., engaged in the manufacture of AAC Blocks, approached the Authority seeking clarity regarding the correct HSN classification and GST rate applicable on the product. The applicant submitted that AAC Blocks are manufactured using fly ash, cement, lime and other materials through a steam-based autoclave curing process. However, ambiguity existed within the industry regarding whether the product should be classified under Chapter 68 as cement based building material or under Chapter 69 as ceramic building blocks.

The applicant contended that AAC Blocks are essentially cement and fly ash based products and therefore merit classification under HSN 6810. It was also submitted that the manufacturing process does not involve firing in a kiln, which is generally associated with ceramic products falling under Chapter 69.

The Authority examined the composition and manufacturing process of AAC Blocks and observed that the products are made primarily from fly ash and cementitious material. It noted that the curing process carried out in an autoclave involves steam pressure treatment and cannot be equated with the firing process required for ceramic goods.

“The manufacturing process of AAC Blocks lacks the essential characteristic of ceramic products, namely firing after shaping, and therefore classification under Chapter 69 is not sustainable.”

The GAAR further observed that Heading 6810 specifically covers articles of cement, concrete or artificial stone, including building blocks and bricks. Since AAC Blocks are used as lightweight construction materials and derive their essential character from cement and fly ash composition, the classification under HSN 6810 11 10 was held to be appropriate.

On the applicable tax rate, the Authority referred to the relevant GST rate notifications governing fly ash-based building materials and held that AAC Blocks falling under HSN 6810 11 10 are taxable at 12% GST, subject to the conditions prescribed under the notifications.

Thus, the Gujarat AAR ruled that AAC Blocks manufactured by Eco Green AAC Products Pvt. Ltd. are classifiable under HSN 6810 11 10 and liable to GST at the rate of 12%.

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