What it means
Rolling shutter sensors are common because they are cheaper, use less power and give good low-light performance. For still or slow scenes the difference is not visible. For fast motion it is. Vertical edges lean, and objects stretch or compress, because the scene moves during readout. On a number plate, characters may tilt or merge, which lowers the OCR read rate.
A short exposure reduces motion blur within each row but does not remove the skew between rows. Only a faster readout or a global shutter does that.
How it applies in India
Rolling shutter cameras are a reasonable choice where vehicles move slowly and stop, such as society gates, parking entries and factory weighbridges. They are a risk on highways, expressways and fast urban corridors, where speeds vary widely. If a tender allows either sensor type, ask the vendor for plate images captured at the top speed of the road, by day and by night.