AirPods 1 gen loses battery life

After active use of AirPods (1 gen) for 1.5 years, the battery capacity decreased by 5-6 times. During viewing, the charge lasts for 1.5 hours, while talking on the phone — 30-40 minutes. In addition, if you discharge the AirPods from 100% to 0%, then the left AirPod remains approximately 10% charged.

Does anyone know why this happened and could Apple’s service center help?

English translation may be not 100% accurate.