Small-molecule APIs: Emissions
Why coal-fired steam makes Indian APIs carbon heavy
What this tab covers The greenhouse-gas footprint per tonne, split by lifecycle phase (feedstock, production, movement, use, end of life), the global total, other environmental impacts, levers and low-carbon routes, India's position, and where the investment opportunity lies.Per kg of API, cradle-to-gate. Intensity: Kekessie et al. 2024 (ACS GCI) PMI; derived (indicative). Global total: Belkhir and Elmeligi, J. Cleaner Production (2019).
Share of footprint by lifecycle phase
Feedstock 50% Production / process 45% Movement 5%Footprint by lifecycle phase
| Phase | Intensity | Share | Main sources of emissions | Notes | Source |
|---|---|---|---|---|---|
| Feedstock | solvents, reagents and KSMs | 50% | virgin solvent make-up, fossil aromatics | solvents are typically the majority of PMI (indicative) | ACS GCI (indicative) |
| Production / process | steam and electricity for reaction, distillation and drying | 45% | coal-heavy grids and coal boilers in India and China | steam dominated process energy for paracetamol in India (Vivar et al. 2025) | Vivar et al. 2025; indicative |
| Movement | sea freight small; air freight for high-value APIs | 5% | air freight | indicative | indicative |
| Use | not applicable for combustion; APIs pass through patients | – | excretion to wastewater | pharmaceutical residues and antimicrobial resistance are the main use-phase impacts | qualitative |
| End of life | incineration of spent solvents and unused medicines | – | solvent incineration emits fossil CO2 | solvent waste incineration is counted here when not in process | qualitative |
Other environmental impacts
Effluent from API clusters (Patancheru-Pashamylaram in Telangana, Ankleshwar and Vapi in Gujarat) has carried high antibiotic concentrations, a driver of antimicrobial resistance. Chlorinated solvents and high-COD effluent are the main local issues.
Levers to cut emissions
- Solvent recovery and substitution (DCM, DMF, NMP to greener solvents)
- Route redesign with biocatalysis and flow to cut PMI
- Renewable power and electric or biomass steam in API clusters
- Zero liquid discharge and AMR-safe effluent standards
India
India's API clusters run largely on coal-fired captive steam and the state grid; a paracetamol case study found India's process energy footprint above France's because of grid and steam (Vivar et al. 2025).
Emission figures are indicative global averages from the life-cycle studies named; actual footprints vary widely by site, energy mix and method.Low-carbon routes
| Route | Intensity | Cost premium | Status | Source |
|---|---|---|---|---|
| Biocatalytic and continuous-flow routes | PMI cuts of half or more in award cases (indicative) | often cost-saving after development | used by originators and leading CDMOs; few Indian generic producers at scale | ACS GCI Pharmaceutical Roundtable (indicative) |