Strategy Guide

This guide goes deeper than the basics on the About page. If you have already played a few runs and want to optimize, you are in the right place.

Understanding City Health

City Health is the single most important number in Green City. It controls building unlocks, decay speed, and whether your city collapses. The raw score is calculated from four components:

• Pollution (0–40 points) — the cleanest cities score 40, severely polluted cities score 0. Pollution scales in tiers, so going from "Clean" to "Moderate" is a much sharper drop than going from "High" to "Severe".
• Happiness (0–30 points) — each happiness point is worth 2 in health, up to 30. Parks, Schools, and EV Transit Hubs are your best happiness sources.
• Energy (0, 10, or 20 points) — net negative energy scores 0, zero scores 10, surplus scores 20. Even one extra Solar Panel can swing this.
• Diversity (0–10 points) — 2 points per unique building type up to 5 types. Easy free points early.

Below 50 displayed health, decay runs at 1.6× normal speed. Stay above 50 if you can — the difference compounds quickly.

Building Combos Guide

Buildings interact through the shared pollution, energy, and happiness pools. Some combinations punch well above their individual stats:

• Solar + Eco House (1:1) — Solar generates enough energy to cover one house's draw, and the house's pollution is offset by any nearby park. The cheapest stable starter combo.
• Wind Farm + Carbon Capture Plant — Carbon Capture wipes out 8 pollution per tick but costs 4 energy. One Wind Farm produces 8 energy and pairs perfectly. This is the Tier 3 endgame anti-pollution stack.
• School + Green Apartments — Schools generate happiness with zero pollution; apartments produce coins and house more population. Together they push happiness near the 30-point cap cheaply.
• Recycling Plant + Factory — A single Factory emits 5 pollution. Two Recycling Plants absorb 5 pollution. If you must run a Factory for income, buffer it with recycling.
• Bike Lane + Market — Bike Lanes produce a small energy surplus and reduce pollution, offsetting the Market's foot-traffic emissions. Good mid-game commerce combo.

Prestige Strategy

Prestige resets your city in exchange for Green Tokens. The key insight: tokens are worth more spent early than hoarded. The Prestige Shop's permanent multipliers compound across every future run.

Recommended spend order for your first few prestiges:

1. Plot Discount — halves first expansion from 800 to 400 coins. Pays for itself on run #2.
2. Starting Coins boost — lets you skip the painful 0-coin opening and place 2–3 buildings on turn one.
3. Coin multiplier upgrades — buy these once you can afford them without delaying expansions.
4. Cosmetic / utility buildings — Streak Fountain and similar unlocks last, after the math is solved.

Don't prestige too early. The token reward scales with population, so a run that gets you to 12 tokens is roughly 4× more efficient than one that gets you 3.

Daily Challenge Tips

Daily challenges rotate every 24 hours and pay 60 / 120 / 200 coins for Easy / Medium / Hard respectively. Tips to clear them efficiently:

• Do challenges that align with your current run — don't build a Factory just to clear a "produce 100 coins from Factory" challenge if you're going carbon-neutral.
• Streaks compound: completing daily challenges multiple days in a row builds your streak, which unlocks the Streak Fountain and bonus rewards.
• Hard challenges often ask for something you would do anyway (place a Tier 3 building, reach 80 City Health). Plan your run around them when possible.

Managing Pollution

Pollution is the single biggest threat to a long run. The pollution score is tiered, not linear: dropping from Clean (0–3) into Moderate (4–8) costs you 10 health points immediately. The breakpoints are:

• 0–3 Clean: 32–40 pollution score
• 4–8 Moderate: 22 pollution score
• 9–15 High: 12 pollution score
• 16–25 Severe: 5 pollution score
• 26+ Critical: 0 pollution score

Practical implications: it's worth burning a tile on a Park or Community Garden just to step down one tier. And the gap between High and Severe is small, so once you've slipped into High, you might as well run a Factory for the income until you can stack absorbers and clean it all up in one push.

The endgame anti-pollution stack is 1 Carbon Capture Plant (−8) + 2 Recycling Plants (−5) + 1 Park (−2) = −15 pollution per tick, more than enough to cancel out 2 Factories and several houses simultaneously.