Science is the study of theory, its verification through observation and experimentation to verify those observations in the context of the theory. If the theory is verifiable through an experiment and a meticulous observation then it is successful otherwise not. Science includes various areas of study like physics, chemistry, mathematics etc. Science is passion of west but the reality is that it has its roots in India also. It would not be wrong to analyze the reasons about why India lagged behind while the west progressed ahead to left India behind in Science.Why Indian science lagged behind the western science and why Western science is more advanced and genuine? Indian Science progresses like anything else through the early years of first century to eleventh century especially astronomy. While Europe was still living in the dark ages under pope and Christianity, Indians had already made progress in the mathematics and astronomical sciences to name a few. An Indian scientist was the first person to cite the idea that the earth revolved round the sun and not the other way round which was a remarkable achievement made thousand years before Copernicus proposed his heliocentric theory. Another Indian scientist proposed theorems on several geometrical figures and other mathematical proofs which seemed several years advanced. It was India which gave the world the idea of zero and numbers.The numbers concept was given by India which was later transferred to Arab World by Arab Scholar which later passed on to Europe. After having achieved so much remarkable scientific discoveries why Indian Science lagged behind?Indian Science never saw the same trajectory of development as seen by western science during the renaissance period. The progress of Science in west began by Newton and other scientists. Indian society was Caste-ridden.Society had strata of castes where every Caste had its own hereditary profession. There were hard lines drawn between the castes and out of these boundaries no one could jump so if a merchant class worker do the work of art he has to do that work only even if he proposed some noble thoughts out of his mouth some heyday was a thorough nonsense as it was not considered his profession. Brahmans were the only privileged class to have some say in intellectual matters while others classes were left devoid of any such privilege. So in a way there was not such development of science was possible in ancient India where there was no freedom of exchange of thoughts and ideas. Once scientific development got broke in eleventh century A.D. it could not had been kept up in the later years.Invention of printing press happened only in 13th century not in India but in China. It was certainly a misfortune for India that it was not invented earlier. Paper is more powerful medium of storing knowledge and passing on this knowledge to future generations, thereby building on the past knowledge. The Indian ancient scientists (as before mentioned names) could not have been able to do so. The knowledge once created could have been lost forever and could not be stored in a reliable and compact book. In contrast western science when in its nascent stages in the fourteenth century could have capitalized on the opportunity as paper was already invented. So a scientist like Newton or Copernicus or Galileo could have passed such knowledge in the form of books. What would have happened if newton could not have passed his knowledge in form of book called the Principia of mathematics or Copernicus would not have published his work of heliocentric theory? Certainly western science could not have progressed as it did. This knowledge in form of books could be then be used by future scientists to further the progress of the western science. Invention of paper cannot be cited as the sole reason for Indian science to not to have progressed. There are some more reasons which needs investigation as what was the real reason for Indian Scientific thought that originated around fourth century B.C. could not carry on to do what western science has achieved.The Chinese traveler Hun-Tseng while visiting India saw well-established universities in modern Bihar. The University had well laid down monasteries and renowned teachers called gurus. The students lived in monasteries and taught in areas of literature, history, science etc. There was a proper medium of teaching and communication between the guru and the student. Many scholars visited University from various countries to learn higher education. There were some well-known teachers. Another University in modern Pakistan was also a great center of learning in north-western part of India. These were great institutes of learning and could have been great harbinger for cultivation of modern scientific thought for Indian in the coming time and could have placed the country on top of the pile in terms of scientific achievements and other knowledge frontiers. But what happened to such well-established centers of learning. The answer to this curious question is India was a hunting ground for plunderers. India was a rich country at that time with large wealth in form of gold and other precious ornaments. Many plunderers from North West invaded India and destroyed its well established establishments including the universities. There were invasions which created new rulers especially of barbaric nature who wanted to destroy such established learning systems and wanted to lay their own method of administration of the state. The ruins of great Indian Universities suggest how they got destroyed by these invasions of loot and destruction. Once destroyed these systems of learning could not be established on large-scale but prevailed on small-scale. Although these centers of leaning were not like the modern university system of west but they do had the potential to become great centers of learning. Western Science progressed with the aid of the universities system. These were the temples of higher learning where scholars could do research and publish their works. This system of universities could be considered as backbone of western science without which progress of science could not had been possible. Indian science could not have flourished without this education system which is obvious and sensible thought. So in a sense absence of such centers of learning was one of the determining factors for Western science having been triumphed while the Indian science which started so early could not had seen the bright day.The broken string of the scientific thought after the eleventh century A.D. could be seen in the reigns of famous rulers like Akbar. There were experts for literature, music and other arts but not even a single expert on science. Besides that there was not any significant work on science written which can suggest that scientific temper prevailed at that time. Although there were enough works of arts like music, literature that could be cited easily. The rulers in the west had experts like Leonardo Da Vinci in Italy and Tyco Brahe was people whose works changed western science. Presence of such geniuses in the courts of rulers suggests how western scientific thought was given respect by rulers at that time when western science was just flourishing. So in a way ruling aristocracy played a great role in progress of western science in an indirect way by encouraging the scholars of such calibers to continue their work by providing the financial support. In India the situation was entirely different and thus one can consider that Science was entirely forgotten and the though of its progress in such a situation was out of question.Science requires inventions like the steam engine or any other work of technology. The Indian climate is not so harsh and severe as compared to the western countries where cold and harsh weather demanded invention of technology. Requirement for clothes demanded invention of machines and other devices. Indian whether being good did not demanded any invention of technology. So climatic conditions were also had role to play. The demand to go long distances in harsh British winter led to the Invention of steam engine. The demand for clothes and other articles of use led to the establishments of factories. While in India the domestic demand of clothes, utensils and other items got fulfilled by small groups of private artists and workers who specialized in a particular work of art.The scientific discoveries happened in form of patches of scientific discoveries but there was no clear trajectory of the progress of Indian science. The trajectory could had continued and completed but it broke in between by the factors as already cited like castes, the breakup of university system, royal patronage, climate, printing invention. In a way these factors suggest that Indian science could not have progressed as western science progressed. So in the end social, political and economic structural differences certainly made Indian science lagged behind the Western Science.