The sink is one of the furniture in the kitchen. The designing of the kitchen sink needs to take into account the size of the kitchen and the designed space of cabinet. The maximum double bowl stainless steel sink is more than 800 millimeters which is less than one meter. Then you need to prepare the space beside the sink for cutting and making the dishes. There's not much room left for the cabinet.
So one 800 millimeters double bowl sink is divided into two small sinks, and then move the edge size of the sink. The sink is designed into one small basin and one large basin. The small basin is 300mm long, while the big basin is 400mm long. This is a reasonable design. The beauty of the sink needs to be coordinated. It's impossible to make a double bowl sink with one bowl very small and the other bowl very big. That's too bad for aesthetics.