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Expert panels/Panel statement
Updated · version 2Issued 12 Sep 2026 at the scheduled revisit · next revisit 12 Mar 2027 · 7 experts · Illustrative

Panel statements: a revisited statement

Should outdoor work in Delhi stop above a set wet-bulb temperature, and at what level?

Yes. Stop heavy outdoor work at 31 °C wet-bulb, high certainty. Lowered from 32 °C after a large 2026 field study found kidney strain starting a degree earlier.

What changed in version 2Revisit held 12 Sep 2026, as scheduled
Threshold32 °C wet-bulb31 °C wet-bulb
CertaintyModerateHigh
Vote5 agree · 2 dissent6 agree · 1 dissent
Evidence3 sources4 sources: added the 2026 Delhi field study
Why: the field study measured kidney strain directly in 4,100 workers, instead of relying on reported illness. Both version 1 dissenters said this was the evidence they were waiting for; one now agrees.
Statement
Answer. Employers should stop heavy outdoor work when wet-bulb temperature reaches 31 °C, and move it to the coolest hours of the day.Certainty. High. Two independent kinds of evidence, lab tolerance and a large field study, now point to the same threshold.What would change it. Evidence that acclimatised workers tolerate higher levels for light work. The panel did not set a threshold for light work.
How the panel voted
6 agree1 dissent
Dissent (Dr. S. Rao): 31 °C is right for heavy work, but a single threshold will be applied to all work in practice. I would publish a separate figure for light work at the same time.
Evidence used
Field study: 4,100 outdoor workers, Delhi, summer 2026Kidney injury markers rose from 31 °C wet-bulb; published Aug 2026New · supports 31 °C
Heat illness reports, Delhi construction sites (2019–2024)Cases rose sharply above 32 °C wet-bulbSupports
Lab heat tolerance, acclimatised adults (2022)Core temperature unsafe after 1 h at 31–32 °C with heavy workSupports
International occupational heat guidelineWork–rest schedules by heat indexContext
Scope of this statement
Light or seated work: no threshold set.Indoor workplaces without cooling.Cities other than Delhi, where humidity patterns differ.
Version history
9 JunQuestion received from the Delhi Heat Action Office
12 JunVersion 1: 32 °C, moderate certainty, 5–2
18 AugDelhi field study published; chair reopens the statement
12 SepVersion 2: 31 °C, high certainty, 6–1
12 Mar 2027Next revisit, before the 2027 heat season
Panel · 7 expertsEach panellist’s vote and declared interests
PIDr. P. IyerOccupational medicine · chairNone declaredAgree
SRDr. S. RaoNephrologyNone declaredDissent
MQDr. M. QureshiEnvironmental epidemiologyNone declaredAgree · was dissent in v1
Requested by
Delhi Heat Action Office · 9 Jun 2026The requester paid for the panel; CitePep chose its members, and the requester saw the statement when it was published.
Cite this statement
CitePep Expert Panel (Iyer P., chair). Work stoppage thresholds for outdoor workers in Delhi heat. Panel statement, version 2. 12 Sep 2026 (version 1: 12 Jun 2026).
Have new evidence?Goes to the chair. If it changes the answer, a new dated version is issued.