Here are reputable Mumbai-based architecture practices known for sustainable / “green” design (short description + why they’re noted). I’ve listed a mix of large firms and smaller studios so you can choose by scale and project type.

• Morphogenesis — large, India-wide practice with a strong sustainability focus and experience in passive-design, energy‑efficiency and green-certified projects. (buildingandinteriors.com)
• Studio Mumbai (Bijoy Jain) — practice known for material-sensitive, low‑tech, climate‑responsive work and use of local craft and natural materials. (en.Wikipedia.org)
• RMA Architects / Rahul Mehrotra — conservation, urbanism and context‑driven design with sustainable material and local‑knowledge approaches. Good for projects that combine heritage sensitivity and sustainability. (Novatr.com)
• Architecture BRIO — Mumbai/Rotterdam practice noted for projects that integrate sustainable design strategies and bioclimatic thinking (residential, institutional, landscape). (en.Wikipedia.org)
• Blurring Boundaries — Mumbai studio focused on biophilic, ecological design and passive cooling/vernacular strategies for tropical climates. Suited to smaller residential and experimental projects. (en.Wikipedia.org)
• Shilpa Architects (Mumbai office) — national firm with a strong record of vernacular/sustainable design approaches and urban projects. (en.Wikipedia.org)
• Abha Narain Lambah / ANL Associates — conservation and adaptive‑reuse practice that frequently works on energy‑sensitive restorations in Mumbai’s built fabric. (en.Wikipedia.org)
• Vikas Dilawari (conservation practice) — renowned conservation architect in Mumbai; sustainable by virtue of repair/adaptive reuse of existing buildings. (en.Wikipedia.org)

How to pick and next steps

• Choose by project type and scale: studios (Blurring Boundaries, Architecture BRIO) for bespoke houses and experimental work; larger firms (Morphogenesis, RMA, Shilpa, HOK) for commercial, institutional or masterplans. (buildingandinteriors.com)
• Ask shortlisted firms for: examples of comparable projects, their sustainability/green certifications (LEED/GREEN/IGBC) if required, passive-design strategies they use, and preliminary fee estimates.
• I can pull contact pages, recent sustainable projects, or compare 3–4 firms against a specific brief (budget, site, building type) if you want — tell me the project type (residential, office, retrofit, etc.) and approximate budget.