The phrase "although harsh" is correct and usable in written English.
It can be used to introduce a contrasting idea or to acknowledge a difficult or severe aspect of a situation while presenting another perspective.
Example: "The feedback was, although harsh, necessary for improvement."
Alternatives: "albeit severe" or "even if tough".
But Sunday's exchange of words, although harsh at times, never led to blows or other violence.
Japan's anti-China sentiment is not rooted in the past, although harsh and prejudiced opinions about China exist.
Dr Trevor Dines, Plantlife's botanical specialist, said: "Although harsh, these stringent new controls are one of the most effective ways to stop species at an early stage of the invasion process.
Although harsh on Taylor, who has never made an international hundred, the decision was incidental to the result of the match, given England's hopeless position at the time.
Although harsh weather held back sales, the trade group said there was more behind the poor figures.
Although the harsh climate restricts agriculture, wheat, oats, and other grains and vegetables are grown on the plateau.
Although the harsh space environment imposes many severe challenges to space pioneers, space exploration is a realistic and profitable goal for long-term humanity survival.
Although that harsh decision initially galvanised Swansea, who went 2-1 ahead through a superb Ayew goal shortly before the interval, Sunderland's numerical advantage eventually told.
A1 TERRAIN AND WEATHER Afghanistan's climate, although as harsh and varied as its terrain, is likely to favor American and British attackers more than it endangers them.
Although the harsh treatment of scholars by the Mongol conquerors, who established the Yuan dynasty (1206 1368), dampened intellectual activity, outstanding Confucian thinkers nevertheless emerged throughout the period.
Although the harsh government crackdown created greater solidarity among exiles, such differences are a sign that the diaspora has not yet jelled into an opposition party.
