can we reduce the awslightsail quota

No its not possible to lower the SSD size for the configuration you specified, All Lightsail database plans come with a fixed SSD size, however you could try using lower amount of memory as seen in the screenshot. DB in lightsail

Hello,

Unfortunately it is not possible to modify the hardware configurations provided in lightsail as it comes as a bundle. The various bundle options available in lightsail is shown in the below link. Please choose the bundle based on your requirements.

• https://aws.amazon.com/lightsail/pricing/