A p-trap is the right thing to put on the wastewater pipe under a kitchen sink. It maintains a water seal on the outlet, and can be easily opened by hand to clear any blockages. All our efforts to find one in Haldwani failed; “nobody buys them here”, so we should “just install a bottle trap” (good for a bathroom sink, not food waste). Finally, we stumbled across indianp-trap.com, whose proprietor promptly shipped us a p-trap from Chennai by Speed Post. Here it is, fully assembled before installation.