Supplier capacity and seasonality in India: festivals, monsoon and peak load

Capacity is a schedule, not a number

A capacity statement usually arrives as a monthly figure: so many tonnes, so many parts, so many shifts. That figure describes an average month. A purchase order does not land in an average month. It lands in a specific week, next to whatever else the plant has booked, with the labour available on that date.

The useful question is not how much the supplier can make in a month. It is how much of the plant is already committed in the weeks you need, and what has to move for your order to take priority. A supplier with spare capacity in June may be full in November, and the difference is not a failure of the equipment.

Capacity also has a shape. A press line can run extra shifts, but a plating line may be limited by effluent treatment, and a heat treatment furnace may be limited by batch size. The bottleneck is often a utility or a finishing step, not the machine that makes the part.

The Indian year has predictable pinch points

India works on a financial year that ends on 31 March. The weeks before that date carry a push to ship, book revenue and close accounts. Suppliers are busy, banks are busy, and transport is busy. A shipment planned for the last week of March is competing with every other exporter in the country.

The festival season runs from around September to November, with Diwali as the anchor. The date moves each year because it follows the lunar calendar. Factories close for a few days to a week, and the weeks around the closure are disrupted by travel, by a shorter working month and by absences that are planned but not always declared in advance.

Other regional festivals matter more than a national calendar suggests. Pongal in Tamil Nadu, Onam in Kerala, Durga Puja in West Bengal, Ganesh Chaturthi in Maharashtra and Bihu in Assam each change the local working pattern. A supplier in Coimbatore and a supplier in Pune do not stop at the same time.

Monsoon, humidity and power

The south west monsoon runs from June to September and covers most of the country. The north east monsoon brings rain to the south east coast from October to December. The direct effect on a factory is usually manageable. The indirect effects are the ones that hurt: road closures, delayed material, wet cartons and a grid that trips.

Humidity matters for materials that are sensitive to it. Coil and sheet can rust in storage, silver plated contacts can tarnish, and hygroscopic moulding granules need drying before they are run. A supplier that stores material in an open shed will have a different reject rate in August than in February.

Power is the other seasonal variable. Summer demand strains the grid, and some states schedule outages or load restrictions. A plant with a diesel generator can keep the presses running, but the cost per unit rises and the generator may not carry the whole load. Ask what is backed up and what stops.

The buyer's own peak lands on top

Most European and North American buyers have their own seasonal peak, and it usually coincides with the Indian festival season. A programme that needs stock before a December shutdown places orders in October, which is exactly when the supplier is managing Diwali, a shorter month and a queue of other customers with the same idea.

The collision is predictable, which means it can be planned. Work back from your own peak, add the transit time, add the supplier's closure, and see where the order has to be placed. If the answer is uncomfortable, the fix belongs in the annual agreement, not in an expedited freight request in November.

A simple capacity calendar, shared with the supplier and updated each quarter, does more than a spreadsheet of past on time delivery. It turns a recurring surprise into a scheduled conversation.

Reading a capacity statement

Ask for the number of machines, the size range, the number of shifts, the working days per month and the share of capacity already committed. Then ask which operation is the constraint. A supplier that quotes a tonnage without naming the bottleneck has given you a sales figure.

Ask how the plant handles a surge. Extra shifts, a second source for plating, or a subcontractor for a simple operation are all valid answers. The follow up question is who controls the quality at the subcontractor, because the certificate still has to travel with the part.

For a long programme, ask for the capacity reserved for your part family, not the total plant capacity. A plant with most of its output committed to other customers has little room for you, whatever the brochure says.

• Machines, tonnage or size range, and the condition of the equipment
• Shifts per day and working days per month, by season
• Committed load for the next two quarters
• The bottleneck operation, stated plainly
• Generator capacity and what it covers
• Subcontract operations and who approves them
• Absenteeism pattern in the festival months
• Typical changeover time between part numbers

Booking capacity in the agreement

A supply agreement can reserve capacity without promising a volume. The usual structure is a rolling forecast with a firm window. The forecast covers twelve months, the firm order covers the lead time, and the supplier commits to capacity for the firm window and to material for the longer window.

Add a peak season clause. It can require the supplier to confirm the festival shutdown dates by a set date each year, to hold a stated buffer of finished parts before the closure, and to give notice if a large order from another customer threatens the reserved capacity.

Warning signs in a capacity conversation

The first warning is a supplier who answers a capacity question with a delivery promise. The second is a promise that does not change when the volume changes. The third is a schedule that is always met by expediting.

• Every order is accepted, whatever the volume
• No named bottleneck and no stated shift pattern
• Subcontracting that appears only after a delay
• No record of machine downtime or maintenance

Building the annual capacity plan

Start with the supplier's shutdown calendar and your own peak. Put both on one page. Mark the weeks where the two collide and decide, in advance, whether to build stock, move the order earlier or accept a longer lead time with a higher freight cost.

Then agree the review cadence. A quarterly capacity review with the forecast, the committed load and the bottleneck status is enough for most programmes. A monthly review is justified where the part is critical or the volume is high.