Patent Infringement

Patent infringement is the commission of a prohibited act with respect to a patented invention without permission from the patent holder. Permission may typically be granted in the form of a license. 

The scope of the patented invention or the extent of protection is defined in theclaims of the granted patent. In other words, the terms of the claims inform the public of what is not allowed without the permission of the patent holder.

Patents are territorial, and infringement is only possible in a country where a patent is in force. For example, if a patent is granted in the United States, then anyone in the United States is prohibited from making, using, selling or importing the patented item, while people in other countries may be free to exploit the patented invention in their country. The scope of protection may vary from country to country, because the patent is examined -or in some countries not substantively examined- by the patent office in each country or region and may be subject to different patentability requirements.

In response to allegations of infringement, an accused infringing party typically asserts one or more of the following:

• that it was not practicing the patented invention, i.e. the invention claimed in the patent (the claims define the extent of protection conferred by a patent);
• that it was not performing any infringing act in the territory covered by the patent (patents are indeed territorial in nature);
• that the patent has expired (since patents have a limited patent term, i.e. a limited lifetime);
• that the patent (or the particular claim(s) alleged to be infringed) is invalid, because the invention in question does not meet the patentability requirements or includes a formal defect, this rendering the patent invalid or unenforceable;
• that it has obtained a license under the patent.

The parties may also resolve their dispute in a settlement, which may involve a licensing agreement, such as a cross-licensingagreement. Private settlements may not always serve the public interest, "because litigating patent disputes to completion tends to generate positive externalities, by clarifying the limits of patent protection if the patent is upheld or encouraging wider use of the innovation if the patent is invalidated".

EXceptions to infringement:

1. Government use : Government whether central or person authorized in this matter can do activities prohibited otherwise by patent act.

2. Research: Making product and exploiting for the purpose of research are allowed.

3.Supply the patented things to government health institutes.

4. Allow to made and evaluate patented product for the purpose of submit report to govenmetor concern  authority.

Reference 

http://www.ssrana.in/Intellectual%20Property/Patents/Patent-Infringement-in-India.aspx
https://en.wikipedia.org/wiki/Patent_infringement