Hi Sara and welcome back!

Introduction

In your introduction, I would suggest having a word like 'However' at the start of the sentence "This has had a negative impact on the present population because..."

It's because the first three sentences build up the positives very nicely (improved medicine, new drugs, government treatment programs). Suddenly, however, you have a negative, so it's important to mark this for the reader.

Word choice:

The reference in the thesis sentence is not very clear:

The finance must also be focussed on creating awareness on health issues.

• The money that governments spend must also... OR
• The health budget must also...
    
• awareness on obesity ==> awareness of obesity
• Nations could earn efficient and skilled workers ==> Nations could benefit from/foster/develop
• labours ==> labourers, workers, employees
• Although funds are needed to cure the diseased croud ==> Although funds are needed to treat disease,
• This has made a negative impact ==> This has had a negative impact

Articles and conjunctions

Government invests on discovering medicines ==> Governments invest in... OR The government invests in...

...because they are dependant on the cure available than preventing the illnesses ==>Make both plural or singular (parallel)

• ...because they have become dependent on cure rather than prevention
• ...because they have become dependent on treatment rather than prevention

• Thus the people must be made to realise the importance of health. Omit "the" before people?
• follow an healthy diet ==> a healthy diet
• It clearly proves that government must spend ==> governments/the government
• In case of a diabetes patient ==> In the case of a diabetes patient
• future complications like diabetes mellitus, hypertension, cardiac problems ==> and cardiac problems
• Proportion of people who suffer from the diseases must also be considered ==> The proportion of people who suffer from the diseases must also be considered

Agreement

• These basic measures protects them ==> protect
• Government invests on discovering medicines => Governments invest OR The government invests

Simplify:

This is possible by taking preventive measures from becoming the victim of the illness. For instance, occupational hazards could be prevented by using dosage alert badges on the labours to save them. Thus the economy of the country inclines with healthy population.

This is possible by taking preventive measures. For instance, penicillin allergies could be avoided by using badges on workers. (This is too specific an example -  could you pick an easier one or make it clearer?).  Thus, the economy of the country develops in line with the health of its population. (Does this follow the previous sentence?)

if it takes steps to educate the society and make population realise and follow the basic measures ==>
if it takes steps to educate the population and help them implement basic health measures

Run-on sentence/Comma Splice/Long sentence

This could be illustrated in case of a diabetes patient with a leg ulcer, if blood glucose levels are not controlled, the non-healing ulcer turns into a gangrene and leads to amputation of the leg.

If blood glucose levels are not controlled in diabetic patients, leg ulcers may turn gangrenous and require amputation of the leg.

Overall, the essay starts very well, but there are some examples in the body that are not very clear or are too detailed. Your sentences are still too long, at an average 17 words. Try to write shorter sentences - you will have fewer errors. Watch for simple agreement and article errors.