Missing Data can occur when no information is provided for one or more items or for a whole unit. Missing Data can also refer to as NA(Not Available) values in pandas.In Pandas missing data is represented by two value:
None: None is a Python singleton object that is often used for missing data in Python code.
NaN : NaN (an acronym for Not a Number), is a special floating-point value recognized by all systems that use the standard IEEE floating-point representation