Simple Explanation
Upstream municipal treatment one source of pollution reduce करती है, but downstream industrial discharge local water quality worsen कर सकती है। Therefore basin-wide settlement attractiveness uniform नहीं होगी; some reaches safer while others hazardous रह सकते हैं। दूसरा विकल्प सही है। Expert analysis में river basin को single homogeneous unit नहीं बल्कि multiple interacting source zones के रूप में देखना चाहिए। / Upstream municipal treatment reduces one source of pollution, but downstream industrial discharge can still worsen local water quality. Settlement attractiveness across the basin will therefore not be uniform; some reaches may improve while others remain hazardous. The second option is correct. Expert analysis should view a river basin as a set of interacting source zones rather than one homogeneous unit.
