In case your company's salary is in general, higher than industry standards, it is possible that the new company will want to reduce the salary levels. More so, if the salary it is paying for similar function and experience is lower. Considering that your company is being acquired (and not merged), it is possible that the new management is going to dictate the terms.
In most cases, unlike what BrightLight says, the sellers do not care about what happens to the employees after they have sold. So it is not necessary that “No Less Benefit” will be in the agreement. However, till you know the details, these are all gossip. For all you know, they may be acquiring the company because its manpower and its efficiency. In that case, they will definitely not be looking for reduction of salary.
While the labour laws do not prevent lowering the salary as such, an across the board reduction, or even selective reduction would come under the concept of "Changing Terms of Employment" and therefore can for an "Industrial Dispute" under the Industrial Dispute Act. The salary levels can not be changed without the consent of the concerned employees.
You need to access where you stand.
1. Why is the company being acquired (loss making, highly profitable, special skillsets, knowledgebase, customers)
2. What is the nature and structure of the company acquiring your employer.
3. What is your function, how important are you to the business and its success
4. Do you have any special skillsets due to which they can or will want to retain you ?
5. Is the new company a brand name that will help you and make your CV stronger in future ?
6. Is it easy to get a new job in your segment ? At the same salary levels ?
Based on the analysis of these, you need to decide whether to stay on or leave. You can make the decision even before the sale takes place. Or you can do it later once you see what your management is doing. Make a rational decision. Do not react to idle rumours.