import httpx

async def get_city_name_async(lat, lon):
    async with httpx.AsyncClient(timeout=5) as client:
        r = await client.get(
            "https://nominatim.openstreetmap.org/reverse",
            params={"lat": lat, "lon": lon, "format": "json", "zoom": 10, "addressdetails": 1},
            headers={"User-Agent": "AreWeBuriedApp/1.0"}
        )
        r.raise_for_status()
        data = r.json()
    address = data.get("address", {})
    return address.get("city") or address.get("town") or address.get("village") or address.get("county") or f"{lat:.2f},{lon:.2f}"