When the topic of maintenance comes, the primary questions is, whether the wife left the matrimonial home due to any curelity on her by her in-laws or did she left on her own.
If she leaves on her own, there is no ground for maintenance. Such orders passed arbitrarily by lower courts are liable to be challenged in higher courts and higher courts could demolish such orders on finding material in your submissions (provided you can prima-facie show that the wife left on her own).
In case she left due to cruelity, then maintenance becomes her right. No man has a right first to marry a girl, then harraass her so that she leaves him and then he can marry another girl and then repeat his deeds. This is the reason, maintenance could not be dependant on the earnings of the wife.
However, still if your income is less or almost equal to what the wife is earning, then the court, exercising its discretion, may pass an order rejecting plea for maintenance. Simply because you are nowhere above her and she deserves to live as equally as your status which she accepted being your wife and not above.
If you case was first heard by Majistrate then you should first move to Sessions Court and then to High Court.