Comparators are tiered; city-level is the exception, not the rule

URBANIZATION--DOU_CITY gives a genuine NYC-vs-national-city-aggregate comparison across many countries, but only for five indicators — it clusters in gridded-geospatial families and the administrative indicators have no spatial dimension. Tier 1 (city aggregates, ~5 indicators), Tier 2 (urban/rural, ~8, low NYC relevance), Tier 3 (national totals, everything else).

Plan against Tier 3 as the default. An earlier version of this entry recommended city aggregates as the primary framing, generalising from PM2.5 alone; corrected the same day.

Caveat to carry onto any Tier 1 chart: NYC sits inside the US city aggregate, roughly 7% of it.

Superseded framing, kept for the record. The question was first posed as: compare NYC to peer cities (which needs a non-UN source) or to nations? The DOU_CITY finding gave a third and better answer, which is the decision above.

⚠️ This paragraph was its own entry in the old single-file decision log, headed "Superseded — peer-comparator framing" and carrying no date. It is folded in here rather than given one: a dateless entry cannot be ordered, and inventing a date to make it sort is the same defaulting this project refuses everywhere else. It is the history of this decision, so it lives inside it.