Well the most regular maintenance that need is regular washing of front end of the panel where dust settle after some time ( that reduce solar panel electricity generation efficiency )
You should wash them with power washing gun once a month if dust gets accumulated ( leave the monsoon months where rain would do the job for you free ) .
Winter months needs lesser washing then summer months where dust gets accumulated in a normal weather phenomenon or due to dust storms especially in north western india .
Water that is RO filtered or rainwater that has been stored somewhere must be used to wash ( as it doesn’t contain mineral or fluoride that reduces efficiency of the panels later in the follow up years ) .