| | Re: otherwise
It's wrong for two reasons :
1) otherwise is not followed by than. Otherwise means if not and is a sentence adverb :
We need to stop at a service station. Otherwise, we're going to run out of petrol. - ie If we don't stop at a service station, we're going to ... etc
Maybe you were confusing it with other than meaning except ? eg He has no friends other than David.
2. But whether you just meant otherwise or other than the sentence still makes no sense. This is made worse by the use of the verb obstructed which means physically blocked - eg The road was obstructed by an overturned lorry.
How can scenes be obstructed ??
So I'm afraid that the sentence is completely unclear as to the meaning. Can you rephrase it using different words to explain what you wanted to say?