Yikes, but Dazz explaination is pretty close to the mark.
In my city council area, Light Industrial or Low Impact as it is sometimes referred to is for warehousing and more quiet work such as machining, light fabrication, light industrial workshop and fitting equipment and is usually mixed with commercial entities in the related industries (ie safety equipment shops and the like). There are specified times that work may happen, and also have noise limits (such as 10 decibels above normal level until such time, then drops off to 5/3 decibels etc).
General Industry or High Impact is 24/7 'make as much noise at whatever hour you like' type zoning, for really heavy fabrication type applications.
My operation is a General Industry, High Impact operation, however I am operating in a Light Industry, Low Impact industrial estate. It took me 8 months to get my DA across the line, but I have intensified my operating area to General Industry, so I can conduct business. I have 2 neighbours who complain, but with the Regulatory Services and WPH&S always kept in the loop when we work outside of the 'normal' Light Industrial hours, plus my annual SIMTARS reports presented usually result in a nice cup of coffee and a chat talking safety $h!t.
pinkboy