Root-Causing Slower Instamart Deliveries in a Tier-1 City Since Last Week

You are a product manager at Swiggy working on Instamart, its quick-commerce grocery delivery service. Since last week, Instamart orders in a Tier-1 city have been taking 10% longer on average than the expected standard delivery time. The slowdown is not confined to one kind of order; it appears across every order type. Find the root cause of the increase. ```hint Let the given facts prune the tree Use what you already know (a large Tier-1 city, every order type affected, a start last week) to set aside whole groups of causes, then split each delivery into its stages to see which one grew. ``` ### Clarifying Questions - Is the expected standard the delivery time promised to customers at checkout, or an internal benchmark, and has that standard or the model that sets it changed recently? - Is this city the only one affected, or do other cities show a smaller version of the same rise? - Did the increase start abruptly on a specific day last week, or build up gradually over the week? - Is it spread evenly across the city's dark stores and hours of the day, or concentrated in certain stores, neighborhoods or peak hours? ### What a Strong Answer Covers - Validating the metric before diagnosing: its definition, any change to the expected standard, data issues, and whether outliers or a shift in order mix explain the average - Splitting delivery time into stages from order placement to handover and locating the stage that grew - Using the three given facts to prune causes, and separating internal causes (store operations, rider supply, product or policy changes) from external ones (weather, traffic, demand, competitors) - A prioritized investigation plan naming the data that would confirm or reject each hypothesis - Fixes matched to the confirmed cause, with the effect on customers and order economics considered ### Follow-up Questions - The data shows that the time from packing to rider pickup grew while travel time stayed flat. What do you investigate next? - If the cause is heavy rain and waterlogging in the city, what would you change, and would you adjust the delivery time shown to customers? - How would you tell whether the slower deliveries are already hurting repeat orders, and which metric would you watch?