Centre withdraws revised earthquake zoning after backlash from Ministries, infrastructure agencies

Centre withdraws revised earthquake zoning after backlash from Ministries, infrastructure agencies

Less than four months after issuing a revision to India’s earthquake zoning framework, the Centre has withdrawn its own notification following a major backlash from several government departments, Metro Rail corporations and infrastructure authorities that apprehended a surge in construction costs of marquee projects nationwide, The Hindu has learnt.

The Bureau of Indian Standards (BIS) had issued a Gazette notification on November 6, 2025, introducing revised earthquake hazard zoning under the updated IS 1893 (Part 1): 2025 code, which governs the earthquake-resistant design of structures. The revised standard was meant to replace the existing IS 1893 (Part 1): 2016 framework that currently guides structural design norms across the country.

However, the revised notification has now been withdrawn through a fresh Gazette notification issued on March 3, 2026, effectively restoring the earlier code with immediate effect.

The reversal follows strong objections from multiple government agencies, including the Ministry of Housing and Urban Affairs (MoHUA), several metro rail corporations across northern India, the National Dam Safety Authority (NDSA) and other infrastructure bodies that flagged the potential impact of the revised probabilistic seismic hazard assessment (PSHA) framework on construction costs.

The development also has major implications for India’s buildings and construction sector, which had begun expressing concern over a potential spike in project costs. Developers had warned that the revised zoning framework could disrupt financing for ongoing projects, with some suggesting that several under-construction high-rise developments could risk turning into “stranded assets” if costs escalated sharply after financial closure.

The BIS notification issued in November last year significantly revised India’s seismic risk framework by incorporating updated PSHA-based modelling and new hazard parameters. Under the proposed classification, more than 60% of India’s landmass would fall under moderate to high earthquake risk zones, representing a major shift in the country’s seismic hazard mapping.

One of the most notable changes in the revised framework was the introduction of a new highest-risk Zone VI, bringing parts of Kashmir, the North-East and the Kutch region of Gujarat under the most stringent seismic design standards. Several other regions across the Himalayan belt were categorised under Zone V, indicating very high seismic vulnerability.

Such changes would have required significant revisions in structural design standards for buildings and infrastructure projects, including stronger foundations, additional reinforcement in structural components and higher safety margins to withstand greater seismic forces.

One of the strongest objections to the revised zoning framework came from within the government itself. In a February 2026 communication to the Cabinet Secretariat, the Ministry of Housing and Urban Affairs flagged “certain technical and financial concerns” arising from the revision of IS 1893.

The MoHUA letter accessed by The Hindu said the proposed revision could have “materially significant financial implications for infrastructure and construction projects”, particularly for large public works such as metro rail systems and urban infrastructure.

Officials familiar with the communication said the Ministry highlighted the implications for Metro Rail projects across several cities, noting that higher hazard values would require stronger structural design and additional reinforcement, potentially leading to a substantial rise in construction costs.

According to officials familiar with the discussions, the National Dam Safety Authority also raised scientific objections to the revised hazard values when the draft circulated among stakeholders in mid-2025.

Highly placed officials at the NDSA said the authority had examined the draft framework and found the proposed hazard parameters significantly higher than what its own assessments suggested.

“We reviewed the draft and felt the values were quite high,” a senior official said. “The hazard value being suggested was much higher than what we were reading from our site investigations.”

Officials added that higher hazard values would automatically translate into higher costs for infrastructure projects.

“Once you classify a region under higher seismic hazard, you need stronger structures and additional safety measures, which increases infrastructure costs,” the official said.

Technical discussions within government agencies also raised questions about the methodology used in the revised probabilistic seismic hazard assessment. Experts acknowledged that the underlying scientific framework was robust but noted that the peak ground acceleration values proposed in the revised model were significantly higher than those typically used in international practice.

At high-level discussions following the November 2025 notification, experts pointed out that peak ground acceleration values in the revised framework were allowed to rise close to 1g, whereas global practice generally keeps them closer to 0.4g. This raised questions about whether India’s hazard parameters should be equated with highly seismic regions such as Japan or Taiwan.

The revised zoning map would also have significant cost implications for infrastructure and housing projects across the country. An official was privy to these meetings explained that even relatively small changes in seismic design parameters can have cascading effects on construction costs.

For instance, a 10% rise in “shear force calculations” can lead to a 1–2% increase in construction costs, as builders would need to use more cement, steel and stronger foundation systems to meet revised structural safety standards.

The impact would not have been uniform across the country. According to preliminary assessments within government agencies, about 45% of India’s landmass would have seen no change in zoning, largely covering relatively stable Zone II and Zone III regions across southern and central India.

However, around 42% of the country would have seen a one-zone increase, including parts of Gujarat, northern India and the North-East, where the shift could have raised construction costs for buildings by 10–20% due to stricter design requirements.

A smaller but critical portion — about 6% of the country, including parts of the Himalayan belt and Gujarat — would have experienced a two-zone increase, which officials said could push construction costs for residential and institutional buildings up by over 30%.

Officials also warned that the impact would be particularly severe for dam infrastructure, where higher seismic hazard values could have pushed construction costs up by 10–20% in several regions and as much as 50% in the highest-risk zones, owing to stricter structural safety requirements.

The cost implications would have extended beyond large infrastructure projects to ordinary housing construction. Officials noted that nearly 80% of housing in India falls under what engineers classify as “non-engineered” construction — typically self-built homes constructed without formal structural design or engineering supervision.

For such homeowners, the revised seismic design norms could have meant significantly higher construction costs, potentially making independent house construction prohibitively expensive in many regions.

By contrast, the remaining 20% of “engineered” construction — largely formal real estate projects in urban areas — would likely have passed on the higher construction costs to buyers, industry observers said.

The real estate sector had also expressed concern about the economic impact of the proposed zoning changes.

A senior executive from a prominent southern India-based real estate developer said zoning classifications already influence construction costs across cities depending on their seismic category.

“In Chennai, we spend more on the structure than we do in Bengaluru or Hyderabad because of the zoning,” the executive said. “Chennai falls under Zone III, while Bengaluru is in Zone II, so even for similar buildings we end up spending more on structural elements.”

He added that the revised zoning framework could have pushed costs even higher across several cities.

“There were quite a few people in the industry who were not happy about this because the cost of construction would have been 15–20% higher than currently,” he said.

Published - March 07, 2026 09:54 pm IST

Source: TheHindu
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