Historical clue formulations

• City haze — 2026-09-16
• Pollution portmanteau — 2026-07-23
• Urban environmental hazard — 2026-07-21
• Unhealthy haze — 2026-07-13
• Some urban pollution — 2026-07-06
• Environmental portmanteau — 2026-07-03
• Manufacturer's gross product? — 2026-06-07
• It's all a haze — 2026-05-21
• Ecological concern — 2026-05-14
• Skyline haze — 2026-02-03
• Environmental concern — 2026-01-23
• Unhealthy haze — 2026-01-07
• Environmental concern in Dr. Seuss's "The Lorax" — 2025-07-17
• Urban irritant — 2025-04-25
• Ecological portmanteau since 1905 — 2025-01-12
• Pollution that can change the colors of a sunset — 2024-09-30
• Pollution portmanteau — 2024-09-02
• Air pollution — 2024-05-06
• Air quality index factor — 2023-12-29
• Air quality concern — 2023-06-28
• Cause of low visibility in some cities — 2023-05-22
• It's hard to see through — 2023-05-12
• Possible cause of a cough — 2023-03-16
• Potential cause of a respiratory problem — 2023-03-11
• Unfresh air — 2022-11-17
• Q: What happens when the ___ clears over Los Angeles? A: UCLA! — 2022-10-19
• Urban air pollution — 2022-07-04
• Cause of some breathing problems — 2022-05-25
• E.P.A. concern — 2022-04-30
• Atmospheric condition that can be caused by wildfires — 2022-02-08
• Delhi issue — 2022-01-16
• Pollution in city skies — 2021-12-27
• Emissions concern — 2021-11-05
• City hazard — 2021-09-12
• Overhead cost of manufacturing? — 2021-07-21
• Polluted air — 2021-04-20
• It's hardly a breath of fresh air — 2020-09-11
• Reason for a bad air day? — 2020-06-14
• Result of atmospheric inversion — 2019-10-24
• Skyline-obscuring pollution — 2019-08-26
• City choker — 2019-04-30
• Unwanted blanket — 2019-04-03
• Urban portmanteau — 2019-02-21
• Environmental concern — 2018-11-22
• Pollution from car emissions, in part — 2018-10-15
• Urban air pollution — 2018-04-16
• Environmental bane — 2017-04-09
• It's hardly a breath of fresh air — 2017-02-10
• Airborne urban hazard — 2015-12-14
• City haze — 2015-10-12