Adjacent Channel Interference can be reduced or eliminated through various operating methods

The simplest methods are reducing power and moving the operation frequency 

Simply moving one additional KHz apart would reduce the adjacent channel interference to the S-1 and S-5 respectively.

It can be seen here that reducing power to a respectable S-9 received signal improves adjacent channel interference while maintaining acceptable communication signals.

Also moving one and a half KHz would reduce the adjacent channel interference below S-0 even for a S9+20 signal.

This however can cause some loss of signal quality by rolling of  the audio highs and lows.

While loss of high and lows for basic voice communications is not really a serious issue, some other modes may be seriously effected.

Some voices and some with hearing impairment may want to forego narrow banding.