You sent your questions to my DMs. In this episode, I answer them — with the science, the logic and the IS code behind every answer.

This is Part 1 of our listener Q&A series on The CODE – India's No.1 Construction Podcast. Rishabh Aggarwal takes on the first 12 questions, all about cement, concrete and shuttering: what to do on site, why it works, and which Indian Standard says so.

Questions answered in this episode:

1. What's the real difference between cement and concrete?

2. 33, 43 or 53 grade — which cement should you use for your home?

3. OPC, PPC or PSC — which is better?

4. Why does cement have a 30-minute minimum setting time?

5. Does cement expire, and how should you store it?

6. How do you check a cement bag on site?

7. What do M15, M20 and M25 mean, and what mix ratio should you use?

8. What happens when you add extra water to concrete?

9. What slump should your concrete have?

10. Why does concrete crack?

11. How many days should you cure concrete?

12. When should shuttering be removed?

This is general guidance. Structural decisions should always come from a licensed structural engineer.

Have a question for Part 2? Send it to Rishabh on Instagram.

If this episode helped you, follow The CODE and leave a rating — it helps more builders, architects and homeowners find the show.

🎙️ The CODE – India's No.1 Construction Podcast

Hosted by Rishabh Aggarwal

📺 Watch on YouTube: @indiasno1constructionpodcast

A building collapsed in Satya Niketan, South Delhi, on September 6, 2026. At least six people didn't come home — most of them students. The building was around 55 years old, mid-renovation, with water reportedly pooling in its basement during repair work.

In this episode, we trace that collapse back through a century of policy that made it possible.

We go back to 1908, when a colonial-era red line called the "Lal Dora" first exempted Delhi's villages from building rules — an exemption independent India inherited and never fully closed. We look at the Delhi Development Authority's own admitted housing shortfall — nearly 4 lakh homes short of its targets, a population undercounted by over a million in its very first master plan. We examine Saidulajab, where Delhi Police formally flagged illegal construction to MCD twice, two months before six people died there in May 2026. And we go clause by clause through the newly notified Master Plan of Delhi 2047 — an 800-page document that admits Delhi's structural safety gaps in its own printed text, while its financial architecture leans heavily toward private developers over citizen-led redevelopment.

This isn't an episode about blame. It's a roadmap — what the government needs to do differently, what agencies need to change, and what citizens can realistically demand and act on, starting today.

Every claim in this episode is sourced and fact-checked. Full source list and gazette clause citations are in the show notes.

This is The CODE. Episode 167.

Show notes / sources:
Al Jazeera, ABC News, Reuters (Satya Niketan collapse, Sept 2026) · Outlook India (Saidulajab collapse, MCD warnings, Sept 2026) · Deccan Herald, The Tribune (Welcome/Seelampur collapse, July 2025) · The Print, Millennium Post (Karawal Nagar, June 2026) · Master Plan of Delhi 2047, Gazette of India, August 2026 · Delhi Development Act, 1957 · Kamal Nath, DDA workshop remarks, 2010 · Manohar Lal, Ministry of Housing and Urban Affairs, April 2026 · Central Bureau of Investigation press releases, 2026 · Supreme Court of India, Bar and Bench, Feb 2025

Delhi-NCR floods every single monsoon — and every year, it's treated like a surprise. In this episode, we go street by street and drain by drain to find out why: a British-era sewer still running under Minto Bridge, a drainage master plan from 1976 that wasn't replaced until 2025, and a written warning about a collapsed sewer in Noida that went unanswered for four years — until someone died.

This one's for anyone who's ever waded through a flooded street in Delhi, Gurugram, or Noida and wondered whether it actually has to be this way.

We cover: the scale of the 2025–2026 flooding, why the city's underground infrastructure hasn't kept pace with its population, what happens when accountability systems exist on paper but not in practice, and how Tokyo, Copenhagen, Kuala Lumpur, and Shenzhen faced the exact same crisis and solved it. We also look at Bengaluru's K-100 drain — twelve kilometres of proof that this is fixable, even here.

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